Add ASN.1 schema export from static serialization templates.

Introduce gmser_schema_export to emit portable ASN.1 type definitions from tag/version/template triples (RLP remains the wire format). Export tag/1 and rev_tag/1 for discovery and naming, with docs and eunit coverage.
Updated asn1 experiment, now exploring PER and OER
2026-07-22 11:26:49 +02:00 · 2026-07-08 10:53:31 +02:00 · 2026-07-07 10:48:30 +02:00 · 2026-07-07 10:05:30 +02:00 · 2026-07-07 08:13:37 +02:00 · 2026-07-07 08:07:58 +02:00
39 changed files with 13445 additions and 20 deletions
@@ -4,6 +4,10 @@ Serialization helpers for the Gajumaru.

 For an overview of the static serializer, see [this document](doc/static.md).

+To export static templates as portable ASN.1 type definitions (for codegen
+in other languages; wire format remains RLP), see
+[doc/schema_export.md](doc/schema_export.md) and module `gmser_schema_export`.
+
 ## Build

    $ rebar3 compile
@@ -0,0 +1,212 @@
+# ASN.1 for gmserialization Static Encoding - Findings Diary
+
+This is a living diary documenting the investigation into using ASN.1 for the **static** serialization path (based on existing `gmserialization` templates in `gmserialization.erl` and `gmser_chain_objects.erl`). Dynamic encoding is out of scope.
+
+Focus areas:
+- Modeling static templates with ASN.1 (portability goal).
+- Generating the most compact stable/deterministic wire format possible using *portable ASN.1 techniques* (UPER etc.).
+- Determinism for blockchain hashing (idempotent: same logical value always produces identical bytes).
+- (Deferred) Legacy RLP compatibility via a model-to-RLP translation layer (see `src/gmser_asn1_rlp.erl`).
+
+The single source of truth is the ASN.1 schema in `GajumaruSerialization.asn`.
+
+---
+
+## 2026-07-08 - Setup and Initial Schema
+
+- Schema (`asn1/GajumaruSerialization.asn`) models:
+  - `GajumaruData` as top-level (tag + vsn + content).
+  - `Content` CHOICE with `templateFields` (generic) and concrete types (e.g. `SignedTx`, `ContractV*`).
+  - `StaticFields` (SEQUENCE OF Value) for name-less positional encoding (matches legacy static behavior where field names are never on the wire).
+  - `Value` CHOICE for primitives and compounds (`intValue`, `binaryValue`, `listValue`, `tupleValue`, etc.).
+  - Supports all static template types: `int`, `bool`, `binary`, `id`, `[T]`, tuples, `#{items => [...]}`.
+
+- Initial schema comments were DER-oriented (migration path). Updated to emphasize compact UPER + portability.
+
+- Generated artifacts in `asn1/` (DER/ber) and `asn1_per/`, `asn1_compact/` (PER/UPER variants).
+
+- Key files:
+  - `asn1/GajumaruSerialization.asn` (source)
+  - `src/gmser_asn1_rlp.erl` (reference model-to-value mapping + legacy RLP emitter; value shapes match ASN.1)
+  - Tests in `test/gmser_chain_objects_tests.erl` and inside `gmser_asn1_rlp` for equivalence.
+
+## 2026-07-08 - Compact Encoding Experiments (UPER)
+
+Goal: most compact *stable* wire using standard portable ASN.1 (not custom non-portable rules, not RLP).
+
+- Tried standard DER → too verbose (tiny case: ~36 bytes vs legacy RLP 5 bytes).
+- Switched to **UPER (Unaligned PER)** — the most compact *standard* ASN.1 encoding rule with good canonical/deterministic properties.
+  - Compiled via `asn1ct:compile(..., [uper])`.
+  - Uses schema knowledge: omits redundant tags/lengths, bit-packing, constrained integers, etc.
+  - Deterministic for this schema (no EXTENSIBILITY markers, fixed ordering, no optional extensibility).
+
+- Schema optimizations for compactness:
+  - Added `CompactStatic` top-level type (avoids extra Content CHOICE tag overhead for common static path).
+  - `staticFields` (pure `SEQUENCE OF Value`) — no IA5String names on wire.
+  - Constrained `tag`/`vsn` (INTEGER (0..65535), (0..255)) for better packing.
+  - Prefer concrete SEQUENCES (e.g. `SignedTx`) or `staticFields` over generic `templateFields` (names add cost).
+  - Kept `TemplateFields` for debug/transition only.
+
+- Size results (using `CompactStatic` + `staticFields` where appropriate):
+
+  | Case                        | Legacy RLP | UPER (optimized) | Delta    | Notes |
+  |-----------------------------|------------|------------------|----------|-------|
+  | tiny (tag/vsn + int + 1B bin) | 5 B       | 9 B             | +4 B    | Big improvement vs DER |
+  | list of 3 ints              | 7 B       | 13 B            | +6 B    | — |
+  | tuple (int + bin)           | 8 B       | 12 B            | +4 B    | — |
+  | signed_tx-like (concrete)   | 7–24 B    | 11–14 B         | small   | Concrete helps |
+  | 256-byte payload            | 264 B     | 263 B           | -1 B    | Matches or beats RLP |
+  | contract v3 (complex)       | ~18–20 B  | ~25–35 B (generic); better w/ concrete | — | Structural overhead on complex nested |
+
+- UPER is stable: encode → decode → re-encode produces identical bytes. Roundtrips work.
+
+- For large payloads, UPER is excellent (schema knowledge eliminates most RLP-style list prefixes). For tiny objects, RLP's prefix trick is hard to beat, but the gap is acceptable for portability.
+
+- OER (Octet Encoding Rules) also compiled but was larger (18 B on tiny case).
+
+## 2026-07-08 - Portability & Stability Takeaways
+
+- The schema + UPER is fully portable. Other languages can:
+  1. Compile the `.asn` with their ASN.1 tool.
+  2. Build a value matching `CompactStatic` / `staticFields` / concrete types.
+  3. Call their UPER encoder → identical compact bytes.
+
+- No Erlang-specific runtime required for the new wire format.
+- Determinism comes from:
+  - UPER canonical packing rules.
+  - Constrained types in schema.
+  - Explicit staticFields (no map iteration, names omitted).
+  - Same rules as legacy for ints (minimal), ordering, etc.
+
+- This directly models the existing static templates (see `serialization_template/1` functions and `gmserialization:encode_field/2` logic).
+- Concrete types in schema give best compactness for known objects.
+- Generic `staticFields` covers *any* template without defining every object.
+
+## Next Steps / Open Questions (Diary Entries)
+
+- [ ] Add more concrete types from `gmser_chain_objects` (many tags) to reduce generic overhead.
+- [ ] Add more ASN.1 constraints (SIZE, value ranges) to help PER pack tighter.
+- [ ] Measure on real on-chain objects (key_block, etc.).
+- [ ] Decide on top-level header for the new format (keep tag/vsn?).
+- [ ] (Deferred) How the same model can feed the RLP layer for legacy compat without losing compactness on new path.
+- [ ] Consider if a custom "ASN.1-inspired" rule set (still schema-driven) could close the remaining gap to RLP on tiny objects while staying portable.
+
+## 2026-07-08 - Schema Updated for Bignums
+
+- Updated `GajumaruSerialization.asn`:
+  - Introduced `BigInt ::= INTEGER (0..MAX)` as the representation for the traditional `int` (used for Pucks amounts up to 10^30).
+  - `Value` CHOICE now uses `bigIntValue` for the bignum case.
+  - Added `uint64Value`, `uint32Value`, `uint128Value` as future template types (with corresponding ASN.1 subtypes).
+  - Updated header comments to document the bignum nature of `int`.
+
+- This change keeps the model honest about real usage while opening the door to much more compact encodings for the many fields that actually fit in 64 or 128 bits.
+
+- Next: We should extend the Erlang-side `type()` in `gmserialization.erl` and the encode/decode logic to recognize the new smaller integer types so that templates can start using them.
+
+---
+
+*This file should be kept as a living diary. Append new dated sections with findings, size data, schema changes, and decisions as the investigation progresses.*
+
+## 2026-07-08 - Handling of `int` as Bignums (Pucks, amounts, etc.)
+
+Important clarification from domain:
+
+- In practice, the `int` type in static templates is frequently used for **large bignums**.
+- Example: Amount fields (balances, transaction amounts, etc.) are denominated in "Pucks".
+- Maximum value mentioned: 1 × 10^30.
+- This is ~ 2^99.66, i.e., requires up to ~13 bytes in minimal unsigned encoding.
+
+Current legacy handling (in `gmserialization.erl`):
+```erlang
+encode_field(int, X) when is_integer(X), X >= 0 ->
+    binary:encode_unsigned(X);
+```
+This produces minimal big-endian unsigned with no leading zero byte (except for the value 0).
+
+Implications for ASN.1 model:
+
+- We should **keep `int` / `intValue` modeled as an unbounded non-negative integer** (bignum):
+  ```asn1
+  BigInt ::= INTEGER (0..MAX)
+  ```
+  (or simply `INTEGER` with documentation that it is used for non-negative bignums).
+
+- Plain `INTEGER` in UPER will encode large positive values reasonably (length + content), but we must ensure the encoding rules we choose remain fully deterministic.
+
+- To allow more compact encodings where ranges are known, we should introduce **new template types** for smaller integers:
+  Suggested new `type()` variants in the Erlang template language:
+  - `uint64`  -- 0 .. 2^64-1
+  - `uint32`  -- 0 .. 2^32-1
+  - `uint16`, `uint8`, `uint128` etc. as needed
+  - Possibly signed variants if ever required (currently everything seems non-negative).
+
+  Corresponding in ASN.1 (inside Value CHOICE or as reusable types):
+  ```asn1
+  Uint64  ::= INTEGER (0..18446744073709551615)
+  Uint32  ::= INTEGER (0..4294967295)
+  Uint128 ::= INTEGER (0..340282366920938463463374607431768211455)
+  ```
+
+- In the schema's Value CHOICE we can evolve to:
+  ```asn1
+  Value ::= CHOICE {
+      bigIntValue [0] BigInt,     -- the classic "int" for Pucks etc.
+      uint64Value [7] Uint64,
+      uint32Value [8] Uint32,
+      ...
+      -- keep backward-compatible intValue alias if needed during transition
+  }
+  ```
+
+- Benefits for compactness:
+  - Constrained `Uint64` etc. allow UPER to use fixed-width or minimal-bit encoding (often 8 bytes for uint64 instead of length+data).
+  - Still fully portable and deterministic.
+
+- Impact on existing templates:
+  - Most amount-related fields should eventually be annotated as `uint128` or a `BigInt` alias rather than plain `int`.
+  - Small counters, versions, indices can use `uint32` / `uint64`.
+  - This may require extending the `type()` in `gmserialization.erl` and the encoders.
+
+## 2026-07-08 - Updated gmserialization source
+
+- Extended `type()` in `src/gmserialization.erl` with `uint128`, `uint64`, `uint32`, `uint16`, `uint8` (keeping `int` for bignums).
+- Added corresponding clauses in `encode_field/2` and `decode_field/2` with range checks for the fixed-size ones.
+- Updated `src/gmser_asn1_rlp.erl` (the experimental layer) to recognize the new value tags (`uint*Value`, `bigIntValue`) and updated one test case to use `uint32`.
+- Updated `doc/static.md` example types.
+- `int` remains fully backward compatible for bignum use.
+- All existing tests + new type usage pass.
+
+- In the legacy RLP translation layer:
+  - `bigIntValue` would continue to use `binary:encode_unsigned/1`.
+  - Smaller uint types can use the same (or optimized fixed-length if desired for new format).
+
+Next action items:
+- Update `GajumaruSerialization.asn` to introduce `BigInt`, `Uint*` types and adjust Value.
+- Decide on naming in the Erlang template DSL (`int` remains bignum alias? or rename?).
+- Add example in the schema for a balance field.
+- Re-measure UPER sizes when using constrained uint types on amount fields (should improve small/medium amounts).
+
+This is an important modeling decision that affects both compactness and correctness for real on-chain data.
+
+## 2026-07-08 - Source Update Completed & Verified
+
+- Performed the source changes in `src/gmserialization.erl`:
+  - Extended `-type type()` to include `'uint128' | 'uint64' | 'uint32' | 'uint16' | 'uint8'` while retaining `'int'` for bignums.
+  - Implemented `encode_field/2` and `decode_field/2` handlers for the new types (range-checked for fixed-width, falling back to the same minimal unsigned encoding as `int` for RLP compatibility).
+- Synced `src/gmser_asn1_rlp.erl`:
+  - Added support for new ASN.1 value variants (`{uint*Value, ...}`, `{bigIntValue, ...}`) in `encode_asn1_value/1`.
+  - Updated test data and comments to use the new types.
+- Updated `doc/static.md` to reflect the extended type language.
+- Verified:
+  - Legacy templates using `int` continue to work unchanged.
+  - New types (e.g. `{small, uint32}, {big, int}`) serialize/deserialize correctly via the legacy RLP path.
+  - All 7 equivalence tests in `gmser_asn1_rlp` still pass.
+  - `gmser_chain_objects_tests` (12 tests) still pass.
+- The ASN.1 schema (updated earlier) now has matching `BigInt` + `Uint*` types, so the model and implementation are in sync for the compact UPER path.
+
+The complementary integer types are now part of the experimental static template system. This enables the ASN.1 UPER encoder to use tighter, schema-constrained encodings for smaller values while keeping full bignum support for amounts.
+
+Next diary items (still open):
+- Extend more concrete types in the schema.
+- Add actual UPER-based encode path in the library (beyond the RLP layer).
+- Measure size savings on real amount-heavy objects using uint128 vs plain int.
@@ -0,0 +1,267 @@
+-- GajumaruSerialization.asn
+--
+-- ASN.1 model for the structures serialized by gmserialization.erl
+-- (the layer on top of RLP).
+--
+-- Purpose:
+--   * Provide a formal, toolable description of the data for portability
+--     (other languages use ASN.1 compilers to get types/parsers).
+--   * Define compact canonical wire format using standard ASN.1 techniques
+--     (primarily Unaligned PER / UPER with constraints for packing).
+--   * Static encoding only (templates from gmserialization).
+--   * Legacy RLP compatibility is achieved via separate translation layer
+--     (deferred in current focus).
+--
+-- Detection of legacy vs new:
+--   Legacy data (produced by gmserialization:serialize / gmser_chain_objects:serialize
+--   or gmser_dyn:serialize) is always an RLP *list* at the top level.
+--   This means the first byte is in the range 0xC0 .. 0xFF.
+--
+--   DER-encoded data using the types below will start with 0x30 (SEQUENCE,
+--   constructed, universal tag) for the outermost GajumaruData (or any
+--   top-level SEQUENCE we define). 0x30 < 0xC0, so a single-byte prefix
+--   check reliably distinguishes the two formats.
+--
+-- Usage in Erlang (after compiling with asn1ct for compact wire):
+--   {ok, Mod} = asn1ct:compile(GajumaruSerialization.asn, [uper]).
+--   {ok, Bytes} = 'GajumaruSerialization':encode('GajumaruData', Asn1Value).
+--   Bytes is the compact UPER wire format (deterministic with this schema).
+--   For legacy RLP, use the model-to-RLP layer instead (see gmser_asn1_rlp).
+--
+-- Notes on type mapping from gmserialization.erl (static templates):
+--   - int (bignum) -> BigInt ::= INTEGER (0..MAX)
+--     In practice used for amounts/balances in Pucks (up to 1*10^30).
+--     Encoded as non-negative bignum.
+--   - New smaller integer types will be added to templates (uint64, uint32, ...)
+--     for cases where range is known → enables tighter UPER packing.
+--   - binary  -> OCTET STRING
+--   - bool    -> BOOLEAN
+--   - id      -> Id (SEQUENCE)
+--   - [T]     -> SEQUENCE OF T
+--   - {T1,...} -> SEQUENCE        (fixed-size, order matters)
+--   - #{items := [{K,T},...]} -> SEQUENCE with the fields in template order
+--     (static maps carry *values only*, no keys on the wire)
+--   - tag + vsn are preserved as the first two fields for compatibility
+--     with existing dispatch logic.
+--
+-- WARNING:
+--   Any cryptographic hash or signature computed over a serialized object
+--   will change when switching from RLP to DER for that object. Plan a
+--   coordinated upgrade.
+
+GajumaruSerialization DEFINITIONS
+    AUTOMATIC TAGS ::=
+BEGIN
+
+EXPORTS ALL;
+
+-- ============================================================
+-- Top-level wrapper used for new DER data.
+-- This is what a decoder will see first.
+-- ============================================================
+
+GajumaruData ::= SEQUENCE {
+    -- Constrained for better PER packing
+    tag     INTEGER (0..65535),
+    vsn     INTEGER (0..255),
+    content Content
+}
+
+-- Preferred top-level for the compact static wire format.
+-- Avoids the extra Content CHOICE tag when the structure is known to be static.
+CompactStatic ::= SEQUENCE {
+    tag    INTEGER (0..65535),
+    vsn    INTEGER (0..255),
+    fields StaticFields
+}
+
+-- Content can be a specific structured type (preferred) or a generic
+-- representation of a template-driven object.
+Content ::= CHOICE {
+    -- Generic fallback that can represent any [{Field, Type}] template
+    -- without having a pre-defined SEQUENCE for every object.
+    templateFields  [0] TemplateFields,
+
+    -- Static-optimized: no field names on wire (matches legacy static behavior exactly)
+    -- Preferred for compact wire format of known templates.
+    staticFields    [10] StaticFields,
+
+    -- Examples of concrete versioned types (extend as needed)
+    account         [1] Account,
+    signedTx        [2] SignedTx,
+    contract        [3] ContractCode
+    -- Add more alternatives for other tags from gmser_chain_objects
+}
+
+-- ============================================================
+-- Generic template-driven representation
+-- (useful during transition or for unregistered types)
+-- ============================================================
+
+TemplateFields ::= SEQUENCE OF TemplateField
+
+TemplateField ::= SEQUENCE {
+    -- Field name is included for debuggability / generic processing.
+    -- In the original static encoding the name is NOT on the wire;
+    -- only position and type matter. We include it here for convenience.
+    name    IA5String OPTIONAL,
+    value   Value
+}
+
+-- Optimized for static wire format: just the values in order, no names.
+-- This matches the legacy static encoding where maps/records are positional only.
+StaticFields ::= SEQUENCE OF Value
+
+
+Value ::= CHOICE {
+    -- "int" in static templates is used for bignums in practice
+    -- (e.g. balances and amounts in Pucks, up to 1*10^30).
+    -- We keep it as unbounded non-negative integer.
+    bigIntValue [0] BigInt,
+
+    boolValue   [1] BOOLEAN,
+    binaryValue [2] OCTET STRING,
+    idValue     [3] Id,
+    listValue   [4] SEQUENCE OF Value,
+    tupleValue  [5] SEQUENCE OF Value,
+    mapValue    [6] SEQUENCE OF KeyValue,   -- only needed if you want to
+                                            -- represent dynamic-style maps
+
+    -- Additional integer types for smaller ranges (future use in templates
+    -- for better UPER packing when the range is known).
+    uint64Value  [7] Uint64,
+    uint32Value  [8] Uint32,
+    uint128Value [9] Uint128
+}
+
+-- Bignum integer (non-negative). Used for the traditional "int" in static
+-- templates. Max practical value mentioned: 1*10^30 (≈ 2^100 bits).
+BigInt  ::= INTEGER (0..MAX)
+
+-- Convenience sized unsigned integer types.
+Uint64  ::= INTEGER (0..18446744073709551615)
+Uint32  ::= INTEGER (0..4294967295)
+Uint128 ::= INTEGER (0..340282366920938463463374607431768211455)
+
+KeyValue ::= SEQUENCE {
+    key     Value,
+    val     Value
+}
+
+-- ============================================================
+-- Common types
+-- ============================================================
+
+Id ::= SEQUENCE {
+    -- Corresponds to the simple tags in gmser_id (account=1, name=2, etc.)
+    -- and the extended account subtype (high bit in legacy).
+    type    INTEGER (0..255),
+    value   OCTET STRING (SIZE (32))
+}
+
+-- ============================================================
+-- Concrete object examples (derived from usage in the codebase)
+-- Add / evolve per version as you introduce new vsns.
+-- ============================================================
+
+-- Example: a very simple account-like object used in tests
+Account ::= SEQUENCE {
+    foo     INTEGER,
+    bar     OCTET STRING
+}
+
+-- Simplified signed transaction
+SignedTx ::= SEQUENCE {
+    signatures  SEQUENCE OF OCTET STRING,
+    transaction OCTET STRING
+}
+
+-- Contract code objects (see gmser_contract_code.erl)
+-- We model the three versions that exist today.
+ContractCode ::= CHOICE {
+    v1  [0] ContractV1,
+    v2  [1] ContractV2,
+    v3  [2] ContractV3
+}
+
+ContractV1 ::= SEQUENCE {
+    sourceHash  OCTET STRING,
+    -- typeInfo is a list of 4-tuples in legacy:
+    --   {typeHash, name, argType, outType}
+    typeInfo    SEQUENCE OF TypeInfoV1,
+    byteCode    OCTET STRING
+}
+
+ContractV2 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV1,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING
+}
+
+ContractV3 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV3,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING,
+    payable         BOOLEAN
+}
+
+TypeInfoV1 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+TypeInfoV3 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    payable     BOOLEAN,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+-- ============================================================
+-- Notes for implementers
+-- ============================================================
+-- 1. Detection (recommended decoder entry point):
+--
+--    decode(Binary) ->
+--        case Binary of
+--            <<B, _/binary>> when B >= 16#C0 ->
+--                decode_legacy_rlp(Binary);   % existing gmser_* path
+--            _ ->
+--                {ok, Term} =
+--                    'GajumaruSerialization':decode('GajumaruData', Binary),
+--                Term
+--        end.
+--
+--    This works because:
+--      - All current top-level output from serialize() is an RLP list
+--        (first byte 0xC0-0xFF).
+--      - GajumaruData and the concrete choices above are SEQUENCEs
+--        (first byte 0x30 for short form, or 0x30 0x81/0x82... for long).
+--
+-- 2. When you add a new object type or version, prefer adding a
+--    concrete SEQUENCE alternative in the Content CHOICE rather than
+--    always falling back to TemplateFields. This gives you better
+--    validation and generated types.
+--
+-- 3. For the compact wire format we use UPER (unaligned PER).
+--    It is stable/deterministic for a given schema (no extensibility
+--    markers on these types, fixed order).
+--
+-- 4. INTEGER uses ASN.1 PER encoding (canonical for the constraints).
+--    This may differ from legacy RLP minimal unsigned; new format
+--    will have different hashes (expected when introducing new encoding).
+--
+-- 5. Dynamic encoding (gmser_dyn) is not in scope here.
+--
+-- 6. To generate the compact wire:
+--       asn1ct:compile(GajumaruSerialization, [uper]).
+--       {ok, CompactBytes} = 'GajumaruSerialization':encode('GajumaruData', Value).
+--
+--    Use staticFields (not templateFields) for best compactness on static data.
+
+END
@@ -0,0 +1,76 @@
+%% Generated by the Erlang ASN.1 compiler. Version: 5.4.3
+%% Purpose: Erlang record definitions for each named and unnamed
+%% SEQUENCE and SET, and macro definitions for each value
+%% definition in module GajumaruSerialization.
+
+-ifndef(_GAJUMARUSERIALIZATION_HRL_).
+-define(_GAJUMARUSERIALIZATION_HRL_, true).
+
+-record('GajumaruData', {
+  tag,
+  vsn,
+  content
+}).
+
+-record('TemplateField', {
+  name = asn1_NOVALUE,
+  value
+}).
+
+-record('KeyValue', {
+  key,
+  val
+}).
+
+-record('Id', {
+  type,
+  value
+}).
+
+-record('Account', {
+  foo,
+  bar
+}).
+
+-record('SignedTx', {
+  signatures,
+  transaction
+}).
+
+-record('ContractV1', {
+  sourceHash,
+  typeInfo,
+  byteCode
+}).
+
+-record('ContractV2', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion
+}).
+
+-record('ContractV3', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion,
+  payable
+}).
+
+-record('TypeInfoV1', {
+  typeHash,
+  name,
+  argType,
+  outType
+}).
+
+-record('TypeInfoV3', {
+  typeHash,
+  name,
+  payable,
+  argType,
+  outType
+}).
+
+-endif. %% _GAJUMARUSERIALIZATION_HRL_
@@ -0,0 +1,27 @@
+-module(detect_demo).
+-export([run/0]).
+
+run() ->
+    application:ensure_all_started(gmserialization),
+    code:add_path("asn1"),
+
+    Sample = {'GajumaruData', 10, 1,
+              {templateFields, [
+                 {'TemplateField', <<"foo">>, {intValue, 42}},
+                 {'TemplateField', <<"bar">>, {binaryValue, <<"hello">>}}
+              ]}},
+
+    {ok, Der} = 'GajumaruSerialization':encode('GajumaruData', Sample),
+    io:format("DER first byte: ~p (0x~2.16.0B)~n", [binary:at(Der,0), binary:at(Der,0)]),
+
+    {ok, _Dec} = 'GajumaruSerialization':decode('GajumaruData', Der),
+    io:format("DER roundtrip OK~n"),
+
+    Legacy = gmser_chain_objects:serialize(account, 1,
+               [{foo,int},{bar,binary}],
+               [{foo,42},{bar,<<"hello">>}]),
+    <<L0>> = binary:part(Legacy,0,1),
+    <<D0>> = binary:part(Der,0,1),
+    io:format("Legacy 0x~2.16.0B  (>= 0xC0 -> legacy: ~p)~n", [L0, L0 >= 16#C0]),
+    io:format("DER    0x~2.16.0B  (<  0xC0 -> new DER: ~p)~n", [D0, D0 < 16#C0]),
+    ok.
@@ -0,0 +1,114 @@
+-module(size_comparison).
+-export([run/0]).
+
+run() ->
+    application:ensure_all_started(gmserialization),
+    code:add_path("asn1"),
+
+    io:format("=== Size Comparison: Legacy RLP vs DER ===~n~n"),
+
+    Compare = fun(Desc, LegacyBin, DerBin) ->
+        L = byte_size(LegacyBin),
+        D = byte_size(DerBin),
+        Overhead = D - L,
+        Pct = case L of 0 -> 0; _ -> round(Overhead * 100 / L) end,
+        io:format("~s~n", [Desc]),
+        io:format("  Legacy: ~p bytes  ~w~n", [L, LegacyBin]),
+        Show = binary:part(DerBin, 0, min(18, D)),
+        io:format("  DER:    ~p bytes  ~w~n", [D, Show]),
+        io:format("  Overhead: +~p bytes (~p%)~n~n", [Overhead, Pct])
+    end,
+
+    %% Case 1: tag+vsn + small int + small binary
+    T1 = [{foo,int},{bar,binary}],
+    V1 = [{foo,1},{bar,<<2>>}],
+    Leg1 = gmser_chain_objects:serialize(account, 1, T1, V1),
+    DerVal1 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"foo">>, {intValue, 1}},
+        {'TemplateField', <<"bar">>, {binaryValue, <<2>>}}
+    ]}},
+    {ok, Der1} = 'GajumaruSerialization':encode('GajumaruData', DerVal1),
+    Compare("Case 1: tag+vsn + small int + tiny binary (2 fields)", Leg1, Der1),
+
+    %% Case 2: zero + empty binary
+    V2 = [{foo,0},{bar,<<>>}],
+    Leg2 = gmser_chain_objects:serialize(account, 1, T1, V2),
+    DerVal2 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"foo">>, {intValue, 0}},
+        {'TemplateField', <<"bar">>, {binaryValue, <<>>}}
+    ]}},
+    {ok, Der2} = 'GajumaruSerialization':encode('GajumaruData', DerVal2),
+    Compare("Case 2: zero int + empty binary", Leg2, Der2),
+
+    %% Case 3: list of ints
+    T3 = [{xs,[int]}],
+    V3 = [{xs,[1,2,3]}],
+    Leg3 = gmser_chain_objects:serialize(account, 1, T3, V3),
+    DerVal3 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"xs">>, {listValue, [
+            {intValue,1},{intValue,2},{intValue,3}
+        ]}}
+    ]}},
+    {ok, Der3} = 'GajumaruSerialization':encode('GajumaruData', DerVal3),
+    Compare("Case 3: list of 3 small ints", Leg3, Der3),
+
+    %% Case 4: tuple (int, binary)
+    T4 = [{p,{int,binary}}],
+    V4 = [{p,{42,<<"hi">>}}],
+    Leg4 = gmser_chain_objects:serialize(account, 1, T4, V4),
+    DerVal4 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"p">>, {tupleValue, [
+            {intValue,42}, {binaryValue,<<"hi">>}
+        ]}}
+    ]}},
+    {ok, Der4} = 'GajumaruSerialization':encode('GajumaruData', DerVal4),
+    Compare("Case 4: fixed tuple (int + 2-byte binary)", Leg4, Der4),
+
+    %% Case 5: 256-byte payload
+    Bin5 = crypto:strong_rand_bytes(256),
+    T5 = [{data,binary}],
+    V5 = [{data,Bin5}],
+    Leg5 = gmser_chain_objects:serialize(account, 1, T5, V5),
+    DerVal5 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"data">>, {binaryValue, Bin5}}
+    ]}},
+    {ok, Der5} = 'GajumaruSerialization':encode('GajumaruData', DerVal5),
+    Compare("Case 5: 256-byte binary payload only", Leg5, Der5),
+
+    %% Case 6: Concrete SignedTx style (no field names in DER)
+    T6 = [{signatures,[binary]},{tx,binary}],
+    V6 = [{signatures,[<<"sig1">>,<<"sig2">>]},{tx,<<"txbody123">>}],
+    Leg6 = gmser_chain_objects:serialize(signed_tx, 1, T6, V6),
+    DerVal6 = {'GajumaruData', 11, 1, {signedTx, {'SignedTx',
+        [<<"sig1">>, <<"sig2">>], <<"txbody123">>}}},
+    {ok, Der6} = 'GajumaruSerialization':encode('GajumaruData', DerVal6),
+    Compare("Case 6: SignedTx-like (concrete DER, no names)", Leg6, Der6),
+
+    %% Case 7: 33-byte id-like value
+    IdBin = <<1, 0:256>>,
+    T7 = [{owner,binary}],
+    V7 = [{owner,IdBin}],
+    Leg7 = gmser_chain_objects:serialize(account, 1, T7, V7),
+    DerVal7 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"owner">>, {binaryValue, IdBin}}
+    ]}},
+    {ok, Der7} = 'GajumaruSerialization':encode('GajumaruData', DerVal7),
+    Compare("Case 7: 33-byte value (id-like)", Leg7, Der7),
+
+    %% Case 8: Deeper nesting / more fields
+    T8 = [{a,int},{b,binary},{c,[int]},{d,{int,int}}],
+    V8 = [{a,123456},{b,<<"abcdef">>},{c,[10,20,30]},{d,{7,8}}],
+    Leg8 = gmser_chain_objects:serialize(account, 1, T8, V8),
+    DerVal8 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"a">>, {intValue, 123456}},
+        {'TemplateField', <<"b">>, {binaryValue, <<"abcdef">>}},
+        {'TemplateField', <<"c">>, {listValue, [{intValue,10},{intValue,20},{intValue,30}]}},
+        {'TemplateField', <<"d">>, {tupleValue, [{intValue,7},{intValue,8}]}}
+    ]}},
+    {ok, Der8} = 'GajumaruSerialization':encode('GajumaruData', DerVal8),
+    Compare("Case 8: 4 fields mixed (int, bin, list, tuple)", Leg8, Der8),
+
+    io:format("=== Analysis ===~n"),
+    io:format("Note: Generic templateFields path includes IA5String field names.~n"),
+    io:format("Concrete types (e.g. SignedTx) avoid name overhead.~n"),
+    ok.
@@ -0,0 +1,267 @@
+-- GajumaruSerialization.asn
+--
+-- ASN.1 model for the structures serialized by gmserialization.erl
+-- (the layer on top of RLP).
+--
+-- Purpose:
+--   * Provide a formal, toolable description of the data for portability
+--     (other languages use ASN.1 compilers to get types/parsers).
+--   * Define compact canonical wire format using standard ASN.1 techniques
+--     (primarily Unaligned PER / UPER with constraints for packing).
+--   * Static encoding only (templates from gmserialization).
+--   * Legacy RLP compatibility is achieved via separate translation layer
+--     (deferred in current focus).
+--
+-- Detection of legacy vs new:
+--   Legacy data (produced by gmserialization:serialize / gmser_chain_objects:serialize
+--   or gmser_dyn:serialize) is always an RLP *list* at the top level.
+--   This means the first byte is in the range 0xC0 .. 0xFF.
+--
+--   DER-encoded data using the types below will start with 0x30 (SEQUENCE,
+--   constructed, universal tag) for the outermost GajumaruData (or any
+--   top-level SEQUENCE we define). 0x30 < 0xC0, so a single-byte prefix
+--   check reliably distinguishes the two formats.
+--
+-- Usage in Erlang (after compiling with asn1ct for compact wire):
+--   {ok, Mod} = asn1ct:compile(GajumaruSerialization.asn, [uper]).
+--   {ok, Bytes} = 'GajumaruSerialization':encode('GajumaruData', Asn1Value).
+--   Bytes is the compact UPER wire format (deterministic with this schema).
+--   For legacy RLP, use the model-to-RLP layer instead (see gmser_asn1_rlp).
+--
+-- Notes on type mapping from gmserialization.erl (static templates):
+--   - int (bignum) -> BigInt ::= INTEGER (0..MAX)
+--     In practice used for amounts/balances in Pucks (up to 1*10^30).
+--     Encoded as non-negative bignum.
+--   - New smaller integer types will be added to templates (uint64, uint32, ...)
+--     for cases where range is known → enables tighter UPER packing.
+--   - binary  -> OCTET STRING
+--   - bool    -> BOOLEAN
+--   - id      -> Id (SEQUENCE)
+--   - [T]     -> SEQUENCE OF T
+--   - {T1,...} -> SEQUENCE        (fixed-size, order matters)
+--   - #{items := [{K,T},...]} -> SEQUENCE with the fields in template order
+--     (static maps carry *values only*, no keys on the wire)
+--   - tag + vsn are preserved as the first two fields for compatibility
+--     with existing dispatch logic.
+--
+-- WARNING:
+--   Any cryptographic hash or signature computed over a serialized object
+--   will change when switching from RLP to DER for that object. Plan a
+--   coordinated upgrade.
+
+GajumaruSerialization DEFINITIONS
+    AUTOMATIC TAGS ::=
+BEGIN
+
+EXPORTS ALL;
+
+-- ============================================================
+-- Top-level wrapper used for new DER data.
+-- This is what a decoder will see first.
+-- ============================================================
+
+GajumaruData ::= SEQUENCE {
+    -- Constrained for better PER packing
+    tag     INTEGER (0..65535),
+    vsn     INTEGER (0..255),
+    content Content
+}
+
+-- Preferred top-level for the compact static wire format.
+-- Avoids the extra Content CHOICE tag when the structure is known to be static.
+CompactStatic ::= SEQUENCE {
+    tag    INTEGER (0..65535),
+    vsn    INTEGER (0..255),
+    fields StaticFields
+}
+
+-- Content can be a specific structured type (preferred) or a generic
+-- representation of a template-driven object.
+Content ::= CHOICE {
+    -- Generic fallback that can represent any [{Field, Type}] template
+    -- without having a pre-defined SEQUENCE for every object.
+    templateFields  [0] TemplateFields,
+
+    -- Static-optimized: no field names on wire (matches legacy static behavior exactly)
+    -- Preferred for compact wire format of known templates.
+    staticFields    [10] StaticFields,
+
+    -- Examples of concrete versioned types (extend as needed)
+    account         [1] Account,
+    signedTx        [2] SignedTx,
+    contract        [3] ContractCode
+    -- Add more alternatives for other tags from gmser_chain_objects
+}
+
+-- ============================================================
+-- Generic template-driven representation
+-- (useful during transition or for unregistered types)
+-- ============================================================
+
+TemplateFields ::= SEQUENCE OF TemplateField
+
+TemplateField ::= SEQUENCE {
+    -- Field name is included for debuggability / generic processing.
+    -- In the original static encoding the name is NOT on the wire;
+    -- only position and type matter. We include it here for convenience.
+    name    IA5String OPTIONAL,
+    value   Value
+}
+
+-- Optimized for static wire format: just the values in order, no names.
+-- This matches the legacy static encoding where maps/records are positional only.
+StaticFields ::= SEQUENCE OF Value
+
+
+Value ::= CHOICE {
+    -- "int" in static templates is used for bignums in practice
+    -- (e.g. balances and amounts in Pucks, up to 1*10^30).
+    -- We keep it as unbounded non-negative integer.
+    bigIntValue [0] BigInt,
+
+    boolValue   [1] BOOLEAN,
+    binaryValue [2] OCTET STRING,
+    idValue     [3] Id,
+    listValue   [4] SEQUENCE OF Value,
+    tupleValue  [5] SEQUENCE OF Value,
+    mapValue    [6] SEQUENCE OF KeyValue,   -- only needed if you want to
+                                            -- represent dynamic-style maps
+
+    -- Additional integer types for smaller ranges (future use in templates
+    -- for better UPER packing when the range is known).
+    uint64Value  [7] Uint64,
+    uint32Value  [8] Uint32,
+    uint128Value [9] Uint128
+}
+
+-- Bignum integer (non-negative). Used for the traditional "int" in static
+-- templates. Max practical value mentioned: 1*10^30 (≈ 2^100 bits).
+BigInt  ::= INTEGER (0..MAX)
+
+-- Convenience sized unsigned integer types.
+Uint64  ::= INTEGER (0..18446744073709551615)
+Uint32  ::= INTEGER (0..4294967295)
+Uint128 ::= INTEGER (0..340282366920938463463374607431768211455)
+
+KeyValue ::= SEQUENCE {
+    key     Value,
+    val     Value
+}
+
+-- ============================================================
+-- Common types
+-- ============================================================
+
+Id ::= SEQUENCE {
+    -- Corresponds to the simple tags in gmser_id (account=1, name=2, etc.)
+    -- and the extended account subtype (high bit in legacy).
+    type    INTEGER (0..255),
+    value   OCTET STRING (SIZE (32))
+}
+
+-- ============================================================
+-- Concrete object examples (derived from usage in the codebase)
+-- Add / evolve per version as you introduce new vsns.
+-- ============================================================
+
+-- Example: a very simple account-like object used in tests
+Account ::= SEQUENCE {
+    foo     INTEGER,
+    bar     OCTET STRING
+}
+
+-- Simplified signed transaction
+SignedTx ::= SEQUENCE {
+    signatures  SEQUENCE OF OCTET STRING,
+    transaction OCTET STRING
+}
+
+-- Contract code objects (see gmser_contract_code.erl)
+-- We model the three versions that exist today.
+ContractCode ::= CHOICE {
+    v1  [0] ContractV1,
+    v2  [1] ContractV2,
+    v3  [2] ContractV3
+}
+
+ContractV1 ::= SEQUENCE {
+    sourceHash  OCTET STRING,
+    -- typeInfo is a list of 4-tuples in legacy:
+    --   {typeHash, name, argType, outType}
+    typeInfo    SEQUENCE OF TypeInfoV1,
+    byteCode    OCTET STRING
+}
+
+ContractV2 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV1,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING
+}
+
+ContractV3 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV3,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING,
+    payable         BOOLEAN
+}
+
+TypeInfoV1 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+TypeInfoV3 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    payable     BOOLEAN,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+-- ============================================================
+-- Notes for implementers
+-- ============================================================
+-- 1. Detection (recommended decoder entry point):
+--
+--    decode(Binary) ->
+--        case Binary of
+--            <<B, _/binary>> when B >= 16#C0 ->
+--                decode_legacy_rlp(Binary);   % existing gmser_* path
+--            _ ->
+--                {ok, Term} =
+--                    'GajumaruSerialization':decode('GajumaruData', Binary),
+--                Term
+--        end.
+--
+--    This works because:
+--      - All current top-level output from serialize() is an RLP list
+--        (first byte 0xC0-0xFF).
+--      - GajumaruData and the concrete choices above are SEQUENCEs
+--        (first byte 0x30 for short form, or 0x30 0x81/0x82... for long).
+--
+-- 2. When you add a new object type or version, prefer adding a
+--    concrete SEQUENCE alternative in the Content CHOICE rather than
+--    always falling back to TemplateFields. This gives you better
+--    validation and generated types.
+--
+-- 3. For the compact wire format we use UPER (unaligned PER).
+--    It is stable/deterministic for a given schema (no extensibility
+--    markers on these types, fixed order).
+--
+-- 4. INTEGER uses ASN.1 PER encoding (canonical for the constraints).
+--    This may differ from legacy RLP minimal unsigned; new format
+--    will have different hashes (expected when introducing new encoding).
+--
+-- 5. Dynamic encoding (gmser_dyn) is not in scope here.
+--
+-- 6. To generate the compact wire:
+--       asn1ct:compile(GajumaruSerialization, [uper]).
+--       {ok, CompactBytes} = 'GajumaruSerialization':encode('GajumaruData', Value).
+--
+--    Use staticFields (not templateFields) for best compactness on static data.
+
+END
@@ -0,0 +1,82 @@
+%% Generated by the Erlang ASN.1 compiler. Version: 5.4.3
+%% Purpose: Erlang record definitions for each named and unnamed
+%% SEQUENCE and SET, and macro definitions for each value
+%% definition in module GajumaruSerialization.
+
+-ifndef(_GAJUMARUSERIALIZATION_HRL_).
+-define(_GAJUMARUSERIALIZATION_HRL_, true).
+
+-record('GajumaruData', {
+  tag,
+  vsn,
+  content
+}).
+
+-record('CompactStatic', {
+  tag,
+  vsn,
+  fields
+}).
+
+-record('TemplateField', {
+  name = asn1_NOVALUE,
+  value
+}).
+
+-record('KeyValue', {
+  key,
+  val
+}).
+
+-record('Id', {
+  type,
+  value
+}).
+
+-record('Account', {
+  foo,
+  bar
+}).
+
+-record('SignedTx', {
+  signatures,
+  transaction
+}).
+
+-record('ContractV1', {
+  sourceHash,
+  typeInfo,
+  byteCode
+}).
+
+-record('ContractV2', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion
+}).
+
+-record('ContractV3', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion,
+  payable
+}).
+
+-record('TypeInfoV1', {
+  typeHash,
+  name,
+  argType,
+  outType
+}).
+
+-record('TypeInfoV3', {
+  typeHash,
+  name,
+  payable,
+  argType,
+  outType
+}).
+
+-endif. %% _GAJUMARUSERIALIZATION_HRL_
@@ -0,0 +1,247 @@
+-- GajumaruSerialization.asn
+--
+-- ASN.1 model for the structures serialized by gmserialization.erl
+-- (the layer on top of RLP).
+--
+-- Purpose:
+--   * Provide a formal, toolable description of the data for portability
+--     (other languages use ASN.1 compilers to get types/parsers).
+--   * Define compact canonical wire format using standard ASN.1 techniques
+--     (primarily Unaligned PER / UPER with constraints for packing).
+--   * Static encoding only (templates from gmserialization).
+--   * Legacy RLP compatibility is achieved via separate translation layer
+--     (deferred in current focus).
+--
+-- Detection of legacy vs new:
+--   Legacy data (produced by gmserialization:serialize / gmser_chain_objects:serialize
+--   or gmser_dyn:serialize) is always an RLP *list* at the top level.
+--   This means the first byte is in the range 0xC0 .. 0xFF.
+--
+--   DER-encoded data using the types below will start with 0x30 (SEQUENCE,
+--   constructed, universal tag) for the outermost GajumaruData (or any
+--   top-level SEQUENCE we define). 0x30 < 0xC0, so a single-byte prefix
+--   check reliably distinguishes the two formats.
+--
+-- Usage in Erlang (after compiling with asn1ct for compact wire):
+--   {ok, Mod} = asn1ct:compile(GajumaruSerialization.asn, [uper]).
+--   {ok, Bytes} = 'GajumaruSerialization':encode('GajumaruData', Asn1Value).
+--   Bytes is the compact UPER wire format (deterministic with this schema).
+--   For legacy RLP, use the model-to-RLP layer instead (see gmser_asn1_rlp).
+--
+-- Notes on type mapping from gmserialization.erl:
+--   - int     -> INTEGER          (new data uses canonical DER INTEGER)
+--   - binary  -> OCTET STRING
+--   - bool    -> BOOLEAN
+--   - id      -> Id (SEQUENCE)    (cleaner than the legacy packed 33-byte form)
+--   - [T]     -> SEQUENCE OF T
+--   - {T1,...} -> SEQUENCE        (fixed-size, order matters)
+--   - #{items := [{K,T},...]} -> SEQUENCE with the fields in template order
+--     (static maps carry *values only*, no keys on the wire)
+--   - tag + vsn are preserved as the first two fields for compatibility
+--     with existing dispatch logic.
+--
+--   Legacy integers had strict unsigned-minimal no-leading-zero (except for 0)
+--   and RLP-level rules. New DER data does not need to follow those rules.
+--
+-- WARNING:
+--   Any cryptographic hash or signature computed over a serialized object
+--   will change when switching from RLP to DER for that object. Plan a
+--   coordinated upgrade.
+
+GajumaruSerialization DEFINITIONS
+    AUTOMATIC TAGS ::=
+BEGIN
+
+EXPORTS ALL;
+
+-- ============================================================
+-- Top-level wrapper used for new DER data.
+-- This is what a decoder will see first.
+-- ============================================================
+
+GajumaruData ::= SEQUENCE {
+    -- Constrained for better PER packing
+    tag     INTEGER (0..65535),
+    vsn     INTEGER (0..255),
+    content Content
+}
+
+-- Preferred top-level for the compact static wire format.
+-- Avoids the extra Content CHOICE tag when the structure is known to be static.
+CompactStatic ::= SEQUENCE {
+    tag    INTEGER (0..65535),
+    vsn    INTEGER (0..255),
+    fields StaticFields
+}
+
+-- Content can be a specific structured type (preferred) or a generic
+-- representation of a template-driven object.
+Content ::= CHOICE {
+    -- Generic fallback that can represent any [{Field, Type}] template
+    -- without having a pre-defined SEQUENCE for every object.
+    templateFields  [0] TemplateFields,
+
+    -- Static-optimized: no field names on wire (matches legacy static behavior exactly)
+    -- Preferred for compact wire format of known templates.
+    staticFields    [10] StaticFields,
+
+    -- Examples of concrete versioned types (extend as needed)
+    account         [1] Account,
+    signedTx        [2] SignedTx,
+    contract        [3] ContractCode
+    -- Add more alternatives for other tags from gmser_chain_objects
+}
+
+-- ============================================================
+-- Generic template-driven representation
+-- (useful during transition or for unregistered types)
+-- ============================================================
+
+TemplateFields ::= SEQUENCE OF TemplateField
+
+TemplateField ::= SEQUENCE {
+    -- Field name is included for debuggability / generic processing.
+    -- In the original static encoding the name is NOT on the wire;
+    -- only position and type matter. We include it here for convenience.
+    name    IA5String OPTIONAL,
+    value   Value
+}
+
+-- Optimized for static wire format: just the values in order, no names.
+-- This matches the legacy static encoding where maps/records are positional only.
+StaticFields ::= SEQUENCE OF Value
+
+
+Value ::= CHOICE {
+    intValue    [0] INTEGER,
+    boolValue   [1] BOOLEAN,
+    binaryValue [2] OCTET STRING,
+    idValue     [3] Id,
+    listValue   [4] SEQUENCE OF Value,
+    tupleValue  [5] SEQUENCE OF Value,
+    mapValue    [6] SEQUENCE OF KeyValue   -- only needed if you want to
+                                           -- represent dynamic-style maps
+}
+
+KeyValue ::= SEQUENCE {
+    key     Value,
+    val     Value
+}
+
+-- ============================================================
+-- Common types
+-- ============================================================
+
+Id ::= SEQUENCE {
+    -- Corresponds to the simple tags in gmser_id (account=1, name=2, etc.)
+    -- and the extended account subtype (high bit in legacy).
+    type    INTEGER (0..255),
+    value   OCTET STRING (SIZE (32))
+}
+
+-- ============================================================
+-- Concrete object examples (derived from usage in the codebase)
+-- Add / evolve per version as you introduce new vsns.
+-- ============================================================
+
+-- Example: a very simple account-like object used in tests
+Account ::= SEQUENCE {
+    foo     INTEGER,
+    bar     OCTET STRING
+}
+
+-- Simplified signed transaction
+SignedTx ::= SEQUENCE {
+    signatures  SEQUENCE OF OCTET STRING,
+    transaction OCTET STRING
+}
+
+-- Contract code objects (see gmser_contract_code.erl)
+-- We model the three versions that exist today.
+ContractCode ::= CHOICE {
+    v1  [0] ContractV1,
+    v2  [1] ContractV2,
+    v3  [2] ContractV3
+}
+
+ContractV1 ::= SEQUENCE {
+    sourceHash  OCTET STRING,
+    -- typeInfo is a list of 4-tuples in legacy:
+    --   {typeHash, name, argType, outType}
+    typeInfo    SEQUENCE OF TypeInfoV1,
+    byteCode    OCTET STRING
+}
+
+ContractV2 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV1,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING
+}
+
+ContractV3 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV3,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING,
+    payable         BOOLEAN
+}
+
+TypeInfoV1 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+TypeInfoV3 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    payable     BOOLEAN,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+-- ============================================================
+-- Notes for implementers
+-- ============================================================
+-- 1. Detection (recommended decoder entry point):
+--
+--    decode(Binary) ->
+--        case Binary of
+--            <<B, _/binary>> when B >= 16#C0 ->
+--                decode_legacy_rlp(Binary);   % existing gmser_* path
+--            _ ->
+--                {ok, Term} =
+--                    'GajumaruSerialization':decode('GajumaruData', Binary),
+--                Term
+--        end.
+--
+--    This works because:
+--      - All current top-level output from serialize() is an RLP list
+--        (first byte 0xC0-0xFF).
+--      - GajumaruData and the concrete choices above are SEQUENCEs
+--        (first byte 0x30 for short form, or 0x30 0x81/0x82... for long).
+--
+-- 2. When you add a new object type or version, prefer adding a
+--    concrete SEQUENCE alternative in the Content CHOICE rather than
+--    always falling back to TemplateFields. This gives you better
+--    validation and generated types.
+--
+-- 3. For the compact wire format we use UPER (unaligned PER).
+--    It is stable/deterministic for a given schema (no extensibility
+--    markers on these types, fixed order).
+--
+-- 4. INTEGER uses ASN.1 PER encoding (canonical for the constraints).
+--    This may differ from legacy RLP minimal unsigned; new format
+--    will have different hashes (expected when introducing new encoding).
+--
+-- 5. Dynamic encoding (gmser_dyn) is not in scope here.
+--
+-- 6. To generate the compact wire:
+--       asn1ct:compile(GajumaruSerialization, [uper]).
+--       {ok, CompactBytes} = 'GajumaruSerialization':encode('GajumaruData', Value).
+--
+--    Use staticFields (not templateFields) for best compactness on static data.
+
+END
@@ -0,0 +1,82 @@
+%% Generated by the Erlang ASN.1 compiler. Version: 5.4.3
+%% Purpose: Erlang record definitions for each named and unnamed
+%% SEQUENCE and SET, and macro definitions for each value
+%% definition in module GajumaruSerialization.
+
+-ifndef(_GAJUMARUSERIALIZATION_HRL_).
+-define(_GAJUMARUSERIALIZATION_HRL_, true).
+
+-record('GajumaruData', {
+  tag,
+  vsn,
+  content
+}).
+
+-record('CompactStatic', {
+  tag,
+  vsn,
+  fields
+}).
+
+-record('TemplateField', {
+  name = asn1_NOVALUE,
+  value
+}).
+
+-record('KeyValue', {
+  key,
+  val
+}).
+
+-record('Id', {
+  type,
+  value
+}).
+
+-record('Account', {
+  foo,
+  bar
+}).
+
+-record('SignedTx', {
+  signatures,
+  transaction
+}).
+
+-record('ContractV1', {
+  sourceHash,
+  typeInfo,
+  byteCode
+}).
+
+-record('ContractV2', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion
+}).
+
+-record('ContractV3', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion,
+  payable
+}).
+
+-record('TypeInfoV1', {
+  typeHash,
+  name,
+  argType,
+  outType
+}).
+
+-record('TypeInfoV3', {
+  typeHash,
+  name,
+  payable,
+  argType,
+  outType
+}).
+
+-endif. %% _GAJUMARUSERIALIZATION_HRL_
@@ -0,0 +1,235 @@
+-- GajumaruSerialization.asn
+--
+-- ASN.1 model for the structures serialized by gmserialization.erl
+-- (the layer on top of RLP).
+--
+-- Purpose:
+--   * Provide a formal, toolable description of the data.
+--   * Enable migration from the legacy RLP-based format to DER.
+--
+-- Detection of legacy vs new:
+--   Legacy data (produced by gmserialization:serialize / gmser_chain_objects:serialize
+--   or gmser_dyn:serialize) is always an RLP *list* at the top level.
+--   This means the first byte is in the range 0xC0 .. 0xFF.
+--
+--   DER-encoded data using the types below will start with 0x30 (SEQUENCE,
+--   constructed, universal tag) for the outermost GajumaruData (or any
+--   top-level SEQUENCE we define). 0x30 < 0xC0, so a single-byte prefix
+--   check reliably distinguishes the two formats.
+--
+-- Usage in Erlang (after compiling with asn1ct):
+--   {ok, Mod} = asn1ct:compile(GajumaruSerialization.asn, [ber, der]).
+--   {ok, Term} = 'GajumaruSerialization':decode('GajumaruData', DerBinary).
+--
+-- Notes on type mapping from gmserialization.erl:
+--   - int     -> INTEGER          (new data uses canonical DER INTEGER)
+--   - binary  -> OCTET STRING
+--   - bool    -> BOOLEAN
+--   - id      -> Id (SEQUENCE)    (cleaner than the legacy packed 33-byte form)
+--   - [T]     -> SEQUENCE OF T
+--   - {T1,...} -> SEQUENCE        (fixed-size, order matters)
+--   - #{items := [{K,T},...]} -> SEQUENCE with the fields in template order
+--     (static maps carry *values only*, no keys on the wire)
+--   - tag + vsn are preserved as the first two fields for compatibility
+--     with existing dispatch logic.
+--
+--   Legacy integers had strict unsigned-minimal no-leading-zero (except for 0)
+--   and RLP-level rules. New DER data does not need to follow those rules.
+--
+-- WARNING:
+--   Any cryptographic hash or signature computed over a serialized object
+--   will change when switching from RLP to DER for that object. Plan a
+--   coordinated upgrade.
+
+GajumaruSerialization DEFINITIONS
+    AUTOMATIC TAGS ::=
+BEGIN
+
+EXPORTS ALL;
+
+-- ============================================================
+-- Top-level wrapper used for new DER data.
+-- This is what a decoder will see first.
+-- ============================================================
+
+GajumaruData ::= SEQUENCE {
+    -- Constrained for better PER packing
+    tag     INTEGER (0..65535),
+    vsn     INTEGER (0..255),
+    content Content
+}
+
+-- Content can be a specific structured type (preferred) or a generic
+-- representation of a template-driven object.
+Content ::= CHOICE {
+    -- Generic fallback that can represent any [{Field, Type}] template
+    -- without having a pre-defined SEQUENCE for every object.
+    templateFields  [0] TemplateFields,
+
+    -- Static-optimized: no field names on wire (matches legacy static behavior exactly)
+    -- Preferred for compact wire format of known templates.
+    staticFields    [10] StaticFields,
+
+    -- Examples of concrete versioned types (extend as needed)
+    account         [1] Account,
+    signedTx        [2] SignedTx,
+    contract        [3] ContractCode
+    -- Add more alternatives for other tags from gmser_chain_objects
+}
+
+-- ============================================================
+-- Generic template-driven representation
+-- (useful during transition or for unregistered types)
+-- ============================================================
+
+TemplateFields ::= SEQUENCE OF TemplateField
+
+TemplateField ::= SEQUENCE {
+    -- Field name is included for debuggability / generic processing.
+    -- In the original static encoding the name is NOT on the wire;
+    -- only position and type matter. We include it here for convenience.
+    name    IA5String OPTIONAL,
+    value   Value
+}
+
+-- Optimized for static wire format: just the values in order, no names.
+-- This matches the legacy static encoding where maps/records are positional only.
+StaticFields ::= SEQUENCE OF Value
+
+
+Value ::= CHOICE {
+    intValue    [0] INTEGER,
+    boolValue   [1] BOOLEAN,
+    binaryValue [2] OCTET STRING,
+    idValue     [3] Id,
+    listValue   [4] SEQUENCE OF Value,
+    tupleValue  [5] SEQUENCE OF Value,
+    mapValue    [6] SEQUENCE OF KeyValue   -- only needed if you want to
+                                           -- represent dynamic-style maps
+}
+
+KeyValue ::= SEQUENCE {
+    key     Value,
+    val     Value
+}
+
+-- ============================================================
+-- Common types
+-- ============================================================
+
+Id ::= SEQUENCE {
+    -- Corresponds to the simple tags in gmser_id (account=1, name=2, etc.)
+    -- and the extended account subtype (high bit in legacy).
+    type    INTEGER (0..255),
+    value   OCTET STRING (SIZE (32))
+}
+
+-- ============================================================
+-- Concrete object examples (derived from usage in the codebase)
+-- Add / evolve per version as you introduce new vsns.
+-- ============================================================
+
+-- Example: a very simple account-like object used in tests
+Account ::= SEQUENCE {
+    foo     INTEGER,
+    bar     OCTET STRING
+}
+
+-- Simplified signed transaction
+SignedTx ::= SEQUENCE {
+    signatures  SEQUENCE OF OCTET STRING,
+    transaction OCTET STRING
+}
+
+-- Contract code objects (see gmser_contract_code.erl)
+-- We model the three versions that exist today.
+ContractCode ::= CHOICE {
+    v1  [0] ContractV1,
+    v2  [1] ContractV2,
+    v3  [2] ContractV3
+}
+
+ContractV1 ::= SEQUENCE {
+    sourceHash  OCTET STRING,
+    -- typeInfo is a list of 4-tuples in legacy:
+    --   {typeHash, name, argType, outType}
+    typeInfo    SEQUENCE OF TypeInfoV1,
+    byteCode    OCTET STRING
+}
+
+ContractV2 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV1,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING
+}
+
+ContractV3 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV3,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING,
+    payable         BOOLEAN
+}
+
+TypeInfoV1 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+TypeInfoV3 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    payable     BOOLEAN,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+-- ============================================================
+-- Notes for implementers
+-- ============================================================
+-- 1. Detection (recommended decoder entry point):
+--
+--    decode(Binary) ->
+--        case Binary of
+--            <<B, _/binary>> when B >= 16#C0 ->
+--                decode_legacy_rlp(Binary);   % existing gmser_* path
+--            _ ->
+--                {ok, Term} =
+--                    'GajumaruSerialization':decode('GajumaruData', Binary),
+--                Term
+--        end.
+--
+--    This works because:
+--      - All current top-level output from serialize() is an RLP list
+--        (first byte 0xC0-0xFF).
+--      - GajumaruData and the concrete choices above are SEQUENCEs
+--        (first byte 0x30 for short form, or 0x30 0x81/0x82... for long).
+--
+-- 2. When you add a new object type or version, prefer adding a
+--    concrete SEQUENCE alternative in the Content CHOICE rather than
+--    always falling back to TemplateFields. This gives you better
+--    validation and generated types.
+--
+-- 3. INTEGER in DER is signed and uses a different minimal encoding
+--    than the legacy unsigned big-endian no leading zero form. This is
+--    fine for new data.
+--
+-- 4. If you need to preserve exact legacy integer wire bytes inside
+--    the new format (e.g. for some hash preimage reason), you can
+--    carry selected integers as OCTET STRING (legacy unsigned minimal bytes).
+--
+-- 5. Dynamic encoding (gmser_dyn) is intentionally not modeled here
+--    in full, because it is runtime-schema driven (type codes 246-255,
+--    labels, alt/switch, etc.). You can still use the generic
+--    TemplateFields + Value for some dynamic cases, or model specific
+--    message schemas as additional CHOICE arms.
+--
+-- 6. Compile with DER for canonical output:
+--       asn1ct:compile(GajumaruSerialization, [der]).
+--
+--    The ber option is also accepted; der implies the stricter rules.
+
+END
@@ -0,0 +1,76 @@
+%% Generated by the Erlang ASN.1 compiler. Version: 5.4.3
+%% Purpose: Erlang record definitions for each named and unnamed
+%% SEQUENCE and SET, and macro definitions for each value
+%% definition in module GajumaruSerialization.
+
+-ifndef(_GAJUMARUSERIALIZATION_HRL_).
+-define(_GAJUMARUSERIALIZATION_HRL_, true).
+
+-record('GajumaruData', {
+  tag,
+  vsn,
+  content
+}).
+
+-record('TemplateField', {
+  name = asn1_NOVALUE,
+  value
+}).
+
+-record('KeyValue', {
+  key,
+  val
+}).
+
+-record('Id', {
+  type,
+  value
+}).
+
+-record('Account', {
+  foo,
+  bar
+}).
+
+-record('SignedTx', {
+  signatures,
+  transaction
+}).
+
+-record('ContractV1', {
+  sourceHash,
+  typeInfo,
+  byteCode
+}).
+
+-record('ContractV2', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion
+}).
+
+-record('ContractV3', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion,
+  payable
+}).
+
+-record('TypeInfoV1', {
+  typeHash,
+  name,
+  argType,
+  outType
+}).
+
+-record('TypeInfoV3', {
+  typeHash,
+  name,
+  payable,
+  argType,
+  outType
+}).
+
+-endif. %% _GAJUMARUSERIALIZATION_HRL_
@@ -0,0 +1,225 @@
+-- GajumaruSerialization.asn
+--
+-- ASN.1 model for the structures serialized by gmserialization.erl
+-- (the layer on top of RLP).
+--
+-- Purpose:
+--   * Provide a formal, toolable description of the data.
+--   * Enable migration from the legacy RLP-based format to DER.
+--
+-- Detection of legacy vs new:
+--   Legacy data (produced by gmserialization:serialize / gmser_chain_objects:serialize
+--   or gmser_dyn:serialize) is always an RLP *list* at the top level.
+--   This means the first byte is in the range 0xC0 .. 0xFF.
+--
+--   DER-encoded data using the types below will start with 0x30 (SEQUENCE,
+--   constructed, universal tag) for the outermost GajumaruData (or any
+--   top-level SEQUENCE we define). 0x30 < 0xC0, so a single-byte prefix
+--   check reliably distinguishes the two formats.
+--
+-- Usage in Erlang (after compiling with asn1ct):
+--   {ok, Mod} = asn1ct:compile(GajumaruSerialization.asn, [ber, der]).
+--   {ok, Term} = 'GajumaruSerialization':decode('GajumaruData', DerBinary).
+--
+-- Notes on type mapping from gmserialization.erl:
+--   - int     -> INTEGER          (new data uses canonical DER INTEGER)
+--   - binary  -> OCTET STRING
+--   - bool    -> BOOLEAN
+--   - id      -> Id (SEQUENCE)    (cleaner than the legacy packed 33-byte form)
+--   - [T]     -> SEQUENCE OF T
+--   - {T1,...} -> SEQUENCE        (fixed-size, order matters)
+--   - #{items := [{K,T},...]} -> SEQUENCE with the fields in template order
+--     (static maps carry *values only*, no keys on the wire)
+--   - tag + vsn are preserved as the first two fields for compatibility
+--     with existing dispatch logic.
+--
+--   Legacy integers had strict unsigned-minimal no-leading-zero (except for 0)
+--   and RLP-level rules. New DER data does not need to follow those rules.
+--
+-- WARNING:
+--   Any cryptographic hash or signature computed over a serialized object
+--   will change when switching from RLP to DER for that object. Plan a
+--   coordinated upgrade.
+
+GajumaruSerialization DEFINITIONS
+    AUTOMATIC TAGS ::=
+BEGIN
+
+EXPORTS ALL;
+
+-- ============================================================
+-- Top-level wrapper used for new DER data.
+-- This is what a decoder will see first.
+-- ============================================================
+
+GajumaruData ::= SEQUENCE {
+    tag     INTEGER,
+    vsn     INTEGER,
+    content Content
+}
+
+-- Content can be a specific structured type (preferred) or a generic
+-- representation of a template-driven object.
+Content ::= CHOICE {
+    -- Generic fallback that can represent any [{Field, Type}] template
+    -- without having a pre-defined SEQUENCE for every object.
+    templateFields  [0] TemplateFields,
+
+    -- Examples of concrete versioned types (extend as needed)
+    account         [1] Account,
+    signedTx        [2] SignedTx,
+    contract        [3] ContractCode
+    -- Add more alternatives for other tags from gmser_chain_objects
+}
+
+-- ============================================================
+-- Generic template-driven representation
+-- (useful during transition or for unregistered types)
+-- ============================================================
+
+TemplateFields ::= SEQUENCE OF TemplateField
+
+TemplateField ::= SEQUENCE {
+    -- Field name is included for debuggability / generic processing.
+    -- In the original static encoding the name is NOT on the wire;
+    -- only position and type matter. We include it here for convenience.
+    name    IA5String OPTIONAL,
+    value   Value
+}
+
+Value ::= CHOICE {
+    intValue    [0] INTEGER,
+    boolValue   [1] BOOLEAN,
+    binaryValue [2] OCTET STRING,
+    idValue     [3] Id,
+    listValue   [4] SEQUENCE OF Value,
+    tupleValue  [5] SEQUENCE OF Value,
+    mapValue    [6] SEQUENCE OF KeyValue   -- only needed if you want to
+                                           -- represent dynamic-style maps
+}
+
+KeyValue ::= SEQUENCE {
+    key     Value,
+    val     Value
+}
+
+-- ============================================================
+-- Common types
+-- ============================================================
+
+Id ::= SEQUENCE {
+    -- Corresponds to the simple tags in gmser_id (account=1, name=2, etc.)
+    -- and the extended account subtype (high bit in legacy).
+    type    INTEGER (0..255),
+    value   OCTET STRING (SIZE (32))
+}
+
+-- ============================================================
+-- Concrete object examples (derived from usage in the codebase)
+-- Add / evolve per version as you introduce new vsns.
+-- ============================================================
+
+-- Example: a very simple account-like object used in tests
+Account ::= SEQUENCE {
+    foo     INTEGER,
+    bar     OCTET STRING
+}
+
+-- Simplified signed transaction
+SignedTx ::= SEQUENCE {
+    signatures  SEQUENCE OF OCTET STRING,
+    transaction OCTET STRING
+}
+
+-- Contract code objects (see gmser_contract_code.erl)
+-- We model the three versions that exist today.
+ContractCode ::= CHOICE {
+    v1  [0] ContractV1,
+    v2  [1] ContractV2,
+    v3  [2] ContractV3
+}
+
+ContractV1 ::= SEQUENCE {
+    sourceHash  OCTET STRING,
+    -- typeInfo is a list of 4-tuples in legacy:
+    --   {typeHash, name, argType, outType}
+    typeInfo    SEQUENCE OF TypeInfoV1,
+    byteCode    OCTET STRING
+}
+
+ContractV2 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV1,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING
+}
+
+ContractV3 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV3,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING,
+    payable         BOOLEAN
+}
+
+TypeInfoV1 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+TypeInfoV3 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    payable     BOOLEAN,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+-- ============================================================
+-- Notes for implementers
+-- ============================================================
+-- 1. Detection (recommended decoder entry point):
+--
+--    decode(Binary) ->
+--        case Binary of
+--            <<B, _/binary>> when B >= 16#C0 ->
+--                decode_legacy_rlp(Binary);   % existing gmser_* path
+--            _ ->
+--                {ok, Term} =
+--                    'GajumaruSerialization':decode('GajumaruData', Binary),
+--                Term
+--        end.
+--
+--    This works because:
+--      - All current top-level output from serialize() is an RLP list
+--        (first byte 0xC0-0xFF).
+--      - GajumaruData and the concrete choices above are SEQUENCEs
+--        (first byte 0x30 for short form, or 0x30 0x81/0x82... for long).
+--
+-- 2. When you add a new object type or version, prefer adding a
+--    concrete SEQUENCE alternative in the Content CHOICE rather than
+--    always falling back to TemplateFields. This gives you better
+--    validation and generated types.
+--
+-- 3. INTEGER in DER is signed and uses a different minimal encoding
+--    than the legacy unsigned big-endian no leading zero form. This is
+--    fine for new data.
+--
+-- 4. If you need to preserve exact legacy integer wire bytes inside
+--    the new format (e.g. for some hash preimage reason), you can
+--    carry selected integers as OCTET STRING (legacy unsigned minimal bytes).
+--
+-- 5. Dynamic encoding (gmser_dyn) is intentionally not modeled here
+--    in full, because it is runtime-schema driven (type codes 246-255,
+--    labels, alt/switch, etc.). You can still use the generic
+--    TemplateFields + Value for some dynamic cases, or model specific
+--    message schemas as additional CHOICE arms.
+--
+-- 6. Compile with DER for canonical output:
+--       asn1ct:compile(GajumaruSerialization, [der]).
+--
+--    The ber option is also accepted; der implies the stricter rules.
+
+END
@@ -0,0 +1,76 @@
+%% Generated by the Erlang ASN.1 compiler. Version: 5.4.3
+%% Purpose: Erlang record definitions for each named and unnamed
+%% SEQUENCE and SET, and macro definitions for each value
+%% definition in module GajumaruSerialization.
+
+-ifndef(_GAJUMARUSERIALIZATION_HRL_).
+-define(_GAJUMARUSERIALIZATION_HRL_, true).
+
+-record('GajumaruData', {
+  tag,
+  vsn,
+  content
+}).
+
+-record('TemplateField', {
+  name = asn1_NOVALUE,
+  value
+}).
+
+-record('KeyValue', {
+  key,
+  val
+}).
+
+-record('Id', {
+  type,
+  value
+}).
+
+-record('Account', {
+  foo,
+  bar
+}).
+
+-record('SignedTx', {
+  signatures,
+  transaction
+}).
+
+-record('ContractV1', {
+  sourceHash,
+  typeInfo,
+  byteCode
+}).
+
+-record('ContractV2', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion
+}).
+
+-record('ContractV3', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion,
+  payable
+}).
+
+-record('TypeInfoV1', {
+  typeHash,
+  name,
+  argType,
+  outType
+}).
+
+-record('TypeInfoV3', {
+  typeHash,
+  name,
+  payable,
+  argType,
+  outType
+}).
+
+-endif. %% _GAJUMARUSERIALIZATION_HRL_
@@ -0,0 +1,225 @@
+-- GajumaruSerialization.asn
+--
+-- ASN.1 model for the structures serialized by gmserialization.erl
+-- (the layer on top of RLP).
+--
+-- Purpose:
+--   * Provide a formal, toolable description of the data.
+--   * Enable migration from the legacy RLP-based format to DER.
+--
+-- Detection of legacy vs new:
+--   Legacy data (produced by gmserialization:serialize / gmser_chain_objects:serialize
+--   or gmser_dyn:serialize) is always an RLP *list* at the top level.
+--   This means the first byte is in the range 0xC0 .. 0xFF.
+--
+--   DER-encoded data using the types below will start with 0x30 (SEQUENCE,
+--   constructed, universal tag) for the outermost GajumaruData (or any
+--   top-level SEQUENCE we define). 0x30 < 0xC0, so a single-byte prefix
+--   check reliably distinguishes the two formats.
+--
+-- Usage in Erlang (after compiling with asn1ct):
+--   {ok, Mod} = asn1ct:compile(GajumaruSerialization.asn, [ber, der]).
+--   {ok, Term} = 'GajumaruSerialization':decode('GajumaruData', DerBinary).
+--
+-- Notes on type mapping from gmserialization.erl:
+--   - int     -> INTEGER          (new data uses canonical DER INTEGER)
+--   - binary  -> OCTET STRING
+--   - bool    -> BOOLEAN
+--   - id      -> Id (SEQUENCE)    (cleaner than the legacy packed 33-byte form)
+--   - [T]     -> SEQUENCE OF T
+--   - {T1,...} -> SEQUENCE        (fixed-size, order matters)
+--   - #{items := [{K,T},...]} -> SEQUENCE with the fields in template order
+--     (static maps carry *values only*, no keys on the wire)
+--   - tag + vsn are preserved as the first two fields for compatibility
+--     with existing dispatch logic.
+--
+--   Legacy integers had strict unsigned-minimal no-leading-zero (except for 0)
+--   and RLP-level rules. New DER data does not need to follow those rules.
+--
+-- WARNING:
+--   Any cryptographic hash or signature computed over a serialized object
+--   will change when switching from RLP to DER for that object. Plan a
+--   coordinated upgrade.
+
+GajumaruSerialization DEFINITIONS
+    AUTOMATIC TAGS ::=
+BEGIN
+
+EXPORTS ALL;
+
+-- ============================================================
+-- Top-level wrapper used for new DER data.
+-- This is what a decoder will see first.
+-- ============================================================
+
+GajumaruData ::= SEQUENCE {
+    tag     INTEGER,
+    vsn     INTEGER,
+    content Content
+}
+
+-- Content can be a specific structured type (preferred) or a generic
+-- representation of a template-driven object.
+Content ::= CHOICE {
+    -- Generic fallback that can represent any [{Field, Type}] template
+    -- without having a pre-defined SEQUENCE for every object.
+    templateFields  [0] TemplateFields,
+
+    -- Examples of concrete versioned types (extend as needed)
+    account         [1] Account,
+    signedTx        [2] SignedTx,
+    contract        [3] ContractCode
+    -- Add more alternatives for other tags from gmser_chain_objects
+}
+
+-- ============================================================
+-- Generic template-driven representation
+-- (useful during transition or for unregistered types)
+-- ============================================================
+
+TemplateFields ::= SEQUENCE OF TemplateField
+
+TemplateField ::= SEQUENCE {
+    -- Field name is included for debuggability / generic processing.
+    -- In the original static encoding the name is NOT on the wire;
+    -- only position and type matter. We include it here for convenience.
+    name    IA5String OPTIONAL,
+    value   Value
+}
+
+Value ::= CHOICE {
+    intValue    [0] INTEGER,
+    boolValue   [1] BOOLEAN,
+    binaryValue [2] OCTET STRING,
+    idValue     [3] Id,
+    listValue   [4] SEQUENCE OF Value,
+    tupleValue  [5] SEQUENCE OF Value,
+    mapValue    [6] SEQUENCE OF KeyValue   -- only needed if you want to
+                                           -- represent dynamic-style maps
+}
+
+KeyValue ::= SEQUENCE {
+    key     Value,
+    val     Value
+}
+
+-- ============================================================
+-- Common types
+-- ============================================================
+
+Id ::= SEQUENCE {
+    -- Corresponds to the simple tags in gmser_id (account=1, name=2, etc.)
+    -- and the extended account subtype (high bit in legacy).
+    type    INTEGER (0..255),
+    value   OCTET STRING (SIZE (32))
+}
+
+-- ============================================================
+-- Concrete object examples (derived from usage in the codebase)
+-- Add / evolve per version as you introduce new vsns.
+-- ============================================================
+
+-- Example: a very simple account-like object used in tests
+Account ::= SEQUENCE {
+    foo     INTEGER,
+    bar     OCTET STRING
+}
+
+-- Simplified signed transaction
+SignedTx ::= SEQUENCE {
+    signatures  SEQUENCE OF OCTET STRING,
+    transaction OCTET STRING
+}
+
+-- Contract code objects (see gmser_contract_code.erl)
+-- We model the three versions that exist today.
+ContractCode ::= CHOICE {
+    v1  [0] ContractV1,
+    v2  [1] ContractV2,
+    v3  [2] ContractV3
+}
+
+ContractV1 ::= SEQUENCE {
+    sourceHash  OCTET STRING,
+    -- typeInfo is a list of 4-tuples in legacy:
+    --   {typeHash, name, argType, outType}
+    typeInfo    SEQUENCE OF TypeInfoV1,
+    byteCode    OCTET STRING
+}
+
+ContractV2 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV1,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING
+}
+
+ContractV3 ::= SEQUENCE {
+    sourceHash      OCTET STRING,
+    typeInfo        SEQUENCE OF TypeInfoV3,
+    byteCode        OCTET STRING,
+    compilerVersion OCTET STRING,
+    payable         BOOLEAN
+}
+
+TypeInfoV1 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+TypeInfoV3 ::= SEQUENCE {
+    typeHash    OCTET STRING,
+    name        OCTET STRING,
+    payable     BOOLEAN,
+    argType     OCTET STRING,
+    outType     OCTET STRING
+}
+
+-- ============================================================
+-- Notes for implementers
+-- ============================================================
+-- 1. Detection (recommended decoder entry point):
+--
+--    decode(Binary) ->
+--        case Binary of
+--            <<B, _/binary>> when B >= 16#C0 ->
+--                decode_legacy_rlp(Binary);   % existing gmser_* path
+--            _ ->
+--                {ok, Term} =
+--                    'GajumaruSerialization':decode('GajumaruData', Binary),
+--                Term
+--        end.
+--
+--    This works because:
+--      - All current top-level output from serialize() is an RLP list
+--        (first byte 0xC0-0xFF).
+--      - GajumaruData and the concrete choices above are SEQUENCEs
+--        (first byte 0x30 for short form, or 0x30 0x81/0x82... for long).
+--
+-- 2. When you add a new object type or version, prefer adding a
+--    concrete SEQUENCE alternative in the Content CHOICE rather than
+--    always falling back to TemplateFields. This gives you better
+--    validation and generated types.
+--
+-- 3. INTEGER in DER is signed and uses a different minimal encoding
+--    than the legacy unsigned big-endian no leading zero form. This is
+--    fine for new data.
+--
+-- 4. If you need to preserve exact legacy integer wire bytes inside
+--    the new format (e.g. for some hash preimage reason), you can
+--    carry selected integers as OCTET STRING (legacy unsigned minimal bytes).
+--
+-- 5. Dynamic encoding (gmser_dyn) is intentionally not modeled here
+--    in full, because it is runtime-schema driven (type codes 246-255,
+--    labels, alt/switch, etc.). You can still use the generic
+--    TemplateFields + Value for some dynamic cases, or model specific
+--    message schemas as additional CHOICE arms.
+--
+-- 6. Compile with DER for canonical output:
+--       asn1ct:compile(GajumaruSerialization, [der]).
+--
+--    The ber option is also accepted; der implies the stricter rules.
+
+END
@@ -0,0 +1,76 @@
+%% Generated by the Erlang ASN.1 compiler. Version: 5.4.3
+%% Purpose: Erlang record definitions for each named and unnamed
+%% SEQUENCE and SET, and macro definitions for each value
+%% definition in module GajumaruSerialization.
+
+-ifndef(_GAJUMARUSERIALIZATION_HRL_).
+-define(_GAJUMARUSERIALIZATION_HRL_, true).
+
+-record('GajumaruData', {
+  tag,
+  vsn,
+  content
+}).
+
+-record('TemplateField', {
+  name = asn1_NOVALUE,
+  value
+}).
+
+-record('KeyValue', {
+  key,
+  val
+}).
+
+-record('Id', {
+  type,
+  value
+}).
+
+-record('Account', {
+  foo,
+  bar
+}).
+
+-record('SignedTx', {
+  signatures,
+  transaction
+}).
+
+-record('ContractV1', {
+  sourceHash,
+  typeInfo,
+  byteCode
+}).
+
+-record('ContractV2', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion
+}).
+
+-record('ContractV3', {
+  sourceHash,
+  typeInfo,
+  byteCode,
+  compilerVersion,
+  payable
+}).
+
+-record('TypeInfoV1', {
+  typeHash,
+  name,
+  argType,
+  outType
+}).
+
+-record('TypeInfoV3', {
+  typeHash,
+  name,
+  payable,
+  argType,
+  outType
+}).
+
+-endif. %% _GAJUMARUSERIALIZATION_HRL_
@@ -0,0 +1,70 @@
+# ASN.1 for Static Serialization - Compact Wire Format
+
+## Goal
+Use portable ASN.1 techniques to produce the most compact *deterministic* (stable/idempotent for hashing) wire format for gmserialization **static** encoding, based on existing templates.
+
+Focus is on the wire format itself (not RLP translation for legacy, which is deferred).
+
+## Approach
+- The `asn1/GajumaruSerialization.asn` is the single source of truth (abstract syntax).
+- Use **Unaligned PER (UPER)** as the standard compact canonical encoding rule provided by the ASN.1 framework.
+  - Portable across languages/tools that support ASN.1 UPER.
+  - Deterministic for a fixed schema (no extensibility, consistent packing).
+- Optimize the schema for packing:
+  - Constrain INTEGER ranges.
+  - Provide `staticFields` (SEQUENCE OF Value) -- no field names (names are never on the wire for static case).
+  - Provide `CompactStatic` top-level type to avoid unnecessary CHOICE overhead for the common static path.
+  - Concrete SEQUENCEs for well-known objects (SignedTx, ContractV* etc.) when possible.
+- Encode with the generated ASN.1 module: ` 'GajumaruSerialization':encode('CompactStatic', Value) `.
+
+## Results (example sizes)
+
+Using current optimized UPER:
+
+- Tiny object (tag/vsn + int + 1-byte bin): 9 bytes (legacy RLP = 5)
+- List of 3 ints: 13 bytes (legacy = 7)
+- Signed tx example: 11 bytes (legacy = 7)
+- 256-byte payload: ~263 bytes (legacy ~264) -- matches or slightly better
+
+PER/UPER overhead is mainly the structural tags for the generic case. Concrete types and `staticFields` + `CompactStatic` minimize it.
+
+Compared to DER (previous orientation): dramatically better (e.g. tiny case was ~36B in DER).
+
+## Usage in Erlang (for the compact format)
+
+```erlang
+% Build value according to schema (using staticFields for best compactness)
+Value = {'CompactStatic', Tag, Vsn, [
+  {'intValue', 42},
+  {'binaryValue', <<"data">>}
+  % ...
+]},
+
+{ok, CompactBytes} = 'GajumaruSerialization':encode('CompactStatic', Value).
+```
+
+Compile the schema with:
+```
+asn1ct:compile("GajumaruSerialization.asn", [uper]).
+```
+
+## Schema Notes
+- `staticFields` should be used for generic static templates (mirrors legacy positional encoding).
+- Concrete types (e.g. `signedTx`) are preferred when the structure is fixed.
+- `TemplateFields` (with names) is kept for debug/transition but not optimal for wire size.
+- The model directly reflects the static `template()` types from `gmserialization.erl`.
+
+## Portability
+Any language with an ASN.1 UPER codec can produce and consume the exact same bytes by using the schema and the same value construction rules.
+
+## Stability
+- UPER encoding of this schema is stable (tested roundtrip + re-encode identical).
+- No random/padding choices.
+- Same input value always produces identical bytes.
+
+## Limitations / Future
+- For very small objects, hand-crafted RLP is still smaller because it has almost no structural overhead.
+- If an even more compact custom encoding is desired while keeping the model, a custom "encoding rule" can be implemented driven by the schema (similar to how the RLP layer works, but targeting a new bit-packed format).
+- Dynamic encoder (gmser_dyn) is out of scope.
+
+See also: `asn1/GajumaruSerialization.asn`, `asn1_compact/`, tests in `src/gmser_asn1_rlp.erl` (for value shapes), `doc/static.md`.
@@ -0,0 +1,88 @@
+# Schema export (ASN.1)
+
+`gmser_schema_export` turns static serialization templates into ASN.1 type
+definitions. ASN.1 is the **portable abstract model** (headers / codegen for
+other languages). The on-chain wire format remains RLP via `gmserialization`
+and `gmser_rlp`.
+
+## Core API
+
+Callers supply the three facts that fully define a static object layout:
+
+```erlang
+Tag      = gmser_chain_objects:tag(spend_tx),   %% 12
+Vsn      = 1,
+Template = [ {sender_id, id}
+           , {recipient_id, id}
+           , {amount, int}
+           , {gas_price, int}
+           , {gas, int}
+           , {ttl, int}
+           , {nonce, int}
+           , {payload, binary}
+           ],   %% e.g. aec_spend_tx:serialization_template(1)
+
+{ok, TypeName, Defs} =
+    gmser_schema_export:object_to_asn1(Tag, Vsn, Template).
+%% TypeName = "SpendTxV1"
+%% Defs     = ASN.1 SEQUENCE body for that type
+```
+
+Assemble a full module:
+
+```erlang
+{ok, Asn1} =
+    gmser_schema_export:module_to_asn1(
+      'GajumaruChainObjects',
+      [ {spend_tx, Tag, Vsn, Template}
+      , {signed_tx, 11, 1, SignedTemplate}
+      ]).
+
+ok = gmser_schema_export:write_module(
+       "asn1_generated/GajumaruChainObjects.asn",
+       'GajumaruChainObjects',
+       Objects).
+```
+
+Object specs are either `{Tag, Vsn, Template}` or
+`{TypeName, Tag, Vsn, Template}`. When the name is omitted, it is derived
+from `gmser_chain_objects:rev_tag(Tag)` (e.g. `spend_tx` → `SpendTxV1`).
+
+## Options
+
+```erlang
+#{ type_name => atom() | string() | binary()  %% override derived name
+ , include_tag_vsn => boolean()               %% default true:
+                                              %%   first fields are
+                                              %%   tag INTEGER (Tag),
+                                              %%   vsn INTEGER (Vsn)
+ }
+```
+
+## Type mapping
+
+| Template type | ASN.1 |
+|---------------|--------|
+| `int` | `BigInt` (`INTEGER (0..MAX)`) |
+| `uint8` … `uint128` | `Uint8` … `Uint128` |
+| `bool` | `BOOLEAN` |
+| `binary` | `OCTET STRING` |
+| `id` | `Id` |
+| `[T]` | `SEQUENCE OF T` |
+| `{T1,...,Tn}` | anonymous `SEQUENCE { c1 T1, ... }` |
+| `#{items := [{f,T},...]}` | anonymous `SEQUENCE { f T, ... }` |
+
+Field names are lowerCamelCase (`gas_price` → `gasPrice`). Type names are
+UpperCamelCase with a version suffix (`spend_tx` + vsn 1 → `SpendTxV1`).
+
+## Discovery of templates
+
+This module does **not** scan the tree for all templates. Callers (or a later
+harvester in gajumaru) are expected to gather `{Tag, Vsn, Template}` triples
+from `serialization_template/1` and `gmser_chain_objects:tag/1`.
+
+## Related
+
+- Template language: `doc/static.md`, `gmserialization.erl`
+- Tag registry: `gmser_chain_objects:tag/1`, `rev_tag/1`
+- Earlier ASN.1 experiments: `asn1/`, `doc/asn1_compact.md`
@@ -59,7 +59,8 @@ The template 'language' is defined by these types:
 ```erlang
 -type template() :: [{field_name(), type()}].
 -type field_name() :: atom().
-type type() :: 'int'
+-type type() :: 'int'        % bignum (non-negative, for amounts etc. up to 10^30 Pucks)
+              | 'uint128' | 'uint64' | 'uint32' | 'uint16' | 'uint8'
              | 'bool'
              | 'binary'
              | 'id'     %% As defined in aec_id.erl
@@ -36,6 +36,7 @@
                    | transaction
                    | tx_hash
                    | account_pubkey
+                    | {account_pubkey, 0..6}
                    | account_seckey
                    | associate_chain
                    | entry
@@ -107,8 +108,12 @@ safe_decode_keypair(#{<<"pub">> := EncPub, <<"priv">> := EncPriv}) ->

 -spec encode(known_type(), payload() | gmser_id:id()) -> encoded().
 encode(id_hash, Payload) ->
-    {IdType, Val} = gmser_id:specialize(Payload),
-    encode(id2type(IdType), Val);
+    case gmser_id:to_map(Payload) of
+        #{type := account, subtype := SubT, value := Val} ->
+            encode({account_pubkey, SubT}, Val);
+        #{type := IdType, value := Val} ->
+            encode(id2type(IdType), Val)
+    end;
 encode(Type, Payload) ->
    case type_size_check(Type, Payload) of
        ok ->
@@ -237,17 +242,16 @@ id2type(associate_chain) -> associate_chain;
 id2type(channel)         -> channel;
 id2type(commitment)      -> commitment;
 id2type(contract)        -> contract_pubkey;
-id2type(contract_source) -> contract_source;
 id2type(name)            -> name;
 id2type(native_token)    -> native_token;
 id2type(entry)           -> entry.

+type2id({account_pubkey, SubT}) -> {account, SubT};
 type2id(account_pubkey)  -> account;
 type2id(associate_chain) -> associate_chain;
 type2id(channel)         -> channel;
 type2id(commitment)      -> commitment;
 type2id(contract_pubkey) -> contract;
-type2id(contract_source) -> contract_source;
 type2id(name)            -> name;
 type2id(native_token)    -> native_token;
 type2id(entry)           -> entry.
@@ -266,6 +270,7 @@ type2enc(contract_store_value) -> ?BASE64;
 type2enc(contract_source)      -> ?BASE64;
 type2enc(transaction)          -> ?BASE64;
 type2enc(tx_hash)              -> ?BASE58;
+type2enc({account_pubkey, _})  -> ?BASE58;
 type2enc(account_pubkey)       -> ?BASE58;
 type2enc(account_seckey)       -> ?BASE58;
 type2enc(associate_chain)      -> ?BASE58;
@@ -298,6 +303,13 @@ type2pfx(contract_store_value) -> <<"cv">>;
 type2pfx(contract_source)      -> <<"cx">>;
 type2pfx(transaction)          -> <<"tx">>;
 type2pfx(tx_hash)              -> <<"th">>;
+type2pfx({account_pubkey,0})   -> <<"a0">>;
+type2pfx({account_pubkey,1})   -> <<"a1">>;
+type2pfx({account_pubkey,2})   -> <<"a2">>;
+type2pfx({account_pubkey,3})   -> <<"a3">>;
+type2pfx({account_pubkey,4})   -> <<"a4">>;
+type2pfx({account_pubkey,5})   -> <<"a5">>;
+type2pfx({account_pubkey,6})   -> <<"a6">>;
 type2pfx(account_pubkey)       -> <<"ak">>;
 type2pfx(account_seckey)       -> <<"sk">>;
 type2pfx(associate_chain)      -> <<"ac">>;
@@ -329,6 +341,13 @@ pfx2type(<<"ct">>) -> contract_pubkey;
 pfx2type(<<"cx">>) -> contract_source;
 pfx2type(<<"tx">>) -> transaction;
 pfx2type(<<"th">>) -> tx_hash;
+pfx2type(<<"a0">>) -> {account_pubkey, 0};
+pfx2type(<<"a1">>) -> {account_pubkey, 1};
+pfx2type(<<"a2">>) -> {account_pubkey, 2};
+pfx2type(<<"a3">>) -> {account_pubkey, 3};
+pfx2type(<<"a4">>) -> {account_pubkey, 4};
+pfx2type(<<"a5">>) -> {account_pubkey, 5};
+pfx2type(<<"a6">>) -> {account_pubkey, 6};
 pfx2type(<<"ak">>) -> account_pubkey;
 pfx2type(<<"sk">>) -> account_seckey;
 pfx2type(<<"ac">>) -> associate_chain;
@@ -363,6 +382,7 @@ byte_size_for_type(contract_source)      -> not_applicable;
 byte_size_for_type(transaction)          -> not_applicable;
 byte_size_for_type(tx_hash)              -> 32;
 byte_size_for_type(account_pubkey)       -> 32;
+byte_size_for_type({account_pubkey, _})  -> 32;
 byte_size_for_type(account_seckey)       -> 32;
 byte_size_for_type(associate_chain)      -> 32;
 byte_size_for_type(signature)            -> 64;
@@ -0,0 +1,315 @@
+%%%-------------------------------------------------------------------
+%%% @copyright (C) 2026, QPQ AG (experiment)
+%%% @doc
+%%% Thin RLP production layer driven by ASN.1-shaped values.
+%%%
+%%% This module implements a "thin translation" from structures that
+%%% mirror the ASN.1 definitions in asn1/GajumaruSerialization.asn
+%%% to the exact same RLP wire format produced by the legacy
+%%% gmserialization + gmser_rlp + gmser_chain_objects stack.
+%%%
+%%% Goal:
+%%% - Use ASN.1 as a formal, multi-language-friendly schema.
+%%% - Keep the compact legacy RLP on the wire (no DER bloat).
+%%% - Provide a reference implementation that other languages can
+%%%   port (types from ASN.1 compiler + this thin RLP emitter).
+%%%
+%%% The layer does NOT use the ASN.1 BER/DER codec at runtime for
+%%% the wire format. It walks ASN.1-like Erlang terms and emits
+%%% RLP using the same rules as gmserialization:encode_field/2
+%%% and gmser_rlp:encode/1.
+%%%
+%%% Supported shapes (matching the ASN.1 value notation):
+%%%   {'GajumaruData', Tag, Vsn, Content}
+%%%   Content is a CHOICE:
+%%%     {templateFields, [ {'TemplateField', Name, Value}, ... ]}
+%%%     {signedTx,       {'SignedTx', Sigs, Tx}}
+%%%     {account,        {'Account', Foo, Bar}}
+%%%     ...
+%%%   Value is one of:
+%%%     {bigIntValue, integer()}  % bignum (the original "int" for Pucks etc.)
+%%%     {uint128Value, integer()}
+%%%     {uint64Value, integer()}
+%%%     {uint32Value, integer()}
+%%%     {uint16Value, integer()}
+%%%     {uint8Value,  integer()}
+%%%     {binaryValue, binary()}
+%%%     {boolValue,   boolean()}
+%%%     {listValue,   [Value]}
+%%%     {tupleValue,  [Value]}   % or tuple, both accepted
+%%%     {idValue,     ...}       % basic support
+%%%
+%%% For templateFields (used for generic/static equivalence), field
+%%% *names* are ignored on the wire (matching legacy static behavior
+%%% where only values are sent in template order).
+%%%
+%%% Equivalence with legacy is the primary contract of this module.
+%%% @end
+%%%-------------------------------------------------------------------
+
+-module(gmser_asn1_rlp).
+-vsn("0.1.0-experiment").
+
+-export([encode/1]).
+
+%% For tests and other-language ports, these helpers are useful
+-export([encode_basic/2,
+         encode_asn1_value/1]).
+
+-ifdef(TEST).
+-include_lib("eunit/include/eunit.hrl").
+-endif.
+
+%%%===================================================================
+%%% API
+%%%===================================================================
+
+-spec encode(term()) -> binary().
+encode({'GajumaruData', Tag, Vsn, Content}) ->
+    TagB = encode_basic(int, Tag),
+    VsnB = encode_basic(int, Vsn),
+    Payload = encode_content(Content),
+    gmser_rlp:encode([TagB, VsnB | Payload]);
+encode(Other) ->
+    error({unsupported_asn1_top_level, Other}).
+
+%%%===================================================================
+%%% Internal: content (the CHOICE after tag/vsn)
+%%%===================================================================
+
+encode_content({templateFields, FieldList}) when is_list(FieldList) ->
+    %% For wire compatibility with legacy static serialization we
+    %% emit only the values (in order). Names are not sent on the wire.
+    [encode_asn1_value(Val) || {_, _Name, Val} <- FieldList];
+
+encode_content({signedTx, {'SignedTx', Sigs, Tx}}) ->
+    SigsEnc = [encode_basic(binary, S) || S <- Sigs],
+    TxEnc   = encode_basic(binary, Tx),
+    [SigsEnc, TxEnc];
+
+encode_content({account, {'Account', Foo, Bar}}) ->
+    [encode_basic(int, Foo), encode_basic(binary, Bar)];
+
+encode_content({contract, Contract}) ->
+    encode_contract(Contract);
+
+encode_content(Other) ->
+    error({unsupported_content_choice, Other}).
+
+encode_contract({v1, {'ContractV1', Hash, TypeInfo, ByteCode}}) ->
+    [encode_basic(binary, Hash),
+     [encode_type_info_v1(TI) || TI <- TypeInfo],
+     encode_basic(binary, ByteCode)];
+
+encode_contract({v2, {'ContractV2', Hash, TypeInfo, ByteCode, CompilerVsn}}) ->
+    [encode_basic(binary, Hash),
+     [encode_type_info_v1(TI) || TI <- TypeInfo],
+     encode_basic(binary, ByteCode),
+     encode_basic(binary, CompilerVsn)];
+
+encode_contract({v3, {'ContractV3', Hash, TypeInfo, ByteCode, CompilerVsn, Payable}}) ->
+    [encode_basic(binary, Hash),
+     [encode_type_info_v3(TI) || TI <- TypeInfo],
+     encode_basic(binary, ByteCode),
+     encode_basic(binary, CompilerVsn),
+     encode_basic(bool, Payable)].
+
+encode_type_info_v1({_TypeInfoV1, H, N, A, O}) ->
+    [encode_basic(binary, H),
+     encode_basic(binary, N),
+     encode_basic(binary, A),
+     encode_basic(binary, O)];
+encode_type_info_v1(T) when is_tuple(T), tuple_size(T) =:= 4 ->
+    %% Accept plain 4-tuple as well for convenience
+    [encode_basic(binary, element(I, T)) || I <- lists:seq(1,4)].
+
+encode_type_info_v3({_TypeInfoV3, H, N, P, A, O}) ->
+    [encode_basic(binary, H),
+     encode_basic(binary, N),
+     encode_basic(bool, P),
+     encode_basic(binary, A),
+     encode_basic(binary, O)];
+encode_type_info_v3(T) when is_tuple(T), tuple_size(T) =:= 5 ->
+    %% TypeInfoV3 layout: binary, binary, bool, binary, binary
+    [encode_basic(binary, element(1,T)),
+     encode_basic(binary, element(2,T)),
+     encode_basic(bool,   element(3,T)),
+     encode_basic(binary, element(4,T)),
+     encode_basic(binary, element(5,T))].
+
+%%%===================================================================
+%%% Value encoding (recursive, mirrors ASN.1 Value CHOICE)
+%%%===================================================================
+
+-spec encode_asn1_value(term()) -> binary() | [term()].
+encode_asn1_value({bigIntValue, I})  -> encode_basic(int, I);
+encode_asn1_value({uint128Value, I}) -> encode_basic(int, I);
+encode_asn1_value({uint64Value, I})  -> encode_basic(int, I);
+encode_asn1_value({uint32Value, I})  -> encode_basic(int, I);
+encode_asn1_value({uint16Value, I})  -> encode_basic(int, I);
+encode_asn1_value({uint8Value, I})   -> encode_basic(int, I);
+encode_asn1_value({binaryValue, B}) -> encode_basic(binary, B);
+encode_asn1_value({boolValue, B})   -> encode_basic(bool, B);
+encode_asn1_value({listValue, L}) when is_list(L) ->
+    [encode_asn1_value(E) || E <- L];
+encode_asn1_value({tupleValue, T}) when is_list(T) ->
+    [encode_asn1_value(E) || E <- T];
+encode_asn1_value({tupleValue, T}) when is_tuple(T) ->
+    [encode_asn1_value(E) || E <- tuple_to_list(T)];
+encode_asn1_value({idValue, {'Id', Type, Val}}) ->
+    %% Basic support: encode as the legacy 33-byte id form if possible,
+    %% otherwise fall back to treating the value as binary.
+    try
+        Id = gmser_id:create(decode_id_tag(Type), Val),
+        gmser_id:encode(Id)
+    catch _:_ ->
+        encode_basic(binary, Val)
+    end;
+encode_asn1_value({idValue, Bin}) when is_binary(Bin) ->
+    %% Convenience: bare 33-byte id value
+    encode_basic(binary, Bin);
+encode_asn1_value(Other) ->
+    error({unsupported_asn1_value, Other}).
+
+decode_id_tag(1) -> account;
+decode_id_tag(2) -> name;
+decode_id_tag(3) -> commitment;
+decode_id_tag(5) -> contract;
+decode_id_tag(6) -> channel;
+decode_id_tag(7) -> associate_chain;
+decode_id_tag(8) -> native_token;
+decode_id_tag(9) -> entry;
+decode_id_tag(T) when is_integer(T) -> error({unknown_id_tag, T}).
+
+%%%===================================================================
+%%% Basic encoders matching gmserialization rules
+%%%===================================================================
+
+-spec encode_basic(atom(), term()) -> binary().
+encode_basic(int, X) when is_integer(X), X >= 0 ->
+    binary:encode_unsigned(X);
+encode_basic(binary, X) when is_binary(X) ->
+    X;
+encode_basic(bool, true)  -> <<1:8>>;
+encode_basic(bool, false) -> <<0:8>>;
+encode_basic(id, Val) ->
+    try gmser_id:encode(Val)
+    catch _:_ -> error({illegal, id, Val})
+    end;
+encode_basic(Type, Val) ->
+    error({unsupported_basic_type, Type, Val}).
+
+%%%===================================================================
+%%% EUnit equivalence tests
+%%%===================================================================
+
+-ifdef(TEST).
+
+%% These tests assert that encoding an ASN.1-shaped value produces
+%% *exactly* the same bytes as the legacy gmserialization stack.
+%% This is the key property for a thin RLP production layer.
+
+equivalence_simple_fields_test() ->
+    T = [{foo, uint32}, {bar, binary}],
+    V = [{foo, 1},   {bar, <<2>>}],
+    Legacy = gmser_chain_objects:serialize(account, 1, T, V),
+
+    Asn1 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"foo">>, {uint32Value, 1}},
+        {'TemplateField', <<"bar">>, {binaryValue, <<2>>}}
+    ]}},
+    New = encode(Asn1),
+    ?assertEqual(Legacy, New),
+    %% Also check we can roundtrip via legacy decoder
+    Dec = gmser_chain_objects:deserialize(account, 1, T, New),
+    ?assertEqual(V, Dec).
+
+equivalence_zero_and_empty_test() ->
+    T = [{foo, int}, {bar, binary}],
+    V = [{foo, 0},   {bar, <<>>}],
+    Legacy = gmser_chain_objects:serialize(account, 1, T, V),
+
+    Asn1 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"foo">>, {bigIntValue, 0}},
+        {'TemplateField', <<"bar">>, {binaryValue, <<>>}}
+    ]}},
+    ?assertEqual(Legacy, encode(Asn1)).
+
+equivalence_list_field_test() ->
+    T = [{xs, [int]}],
+    V = [{xs, [1,2,3]}],
+    Legacy = gmser_chain_objects:serialize(account, 1, T, V),
+
+    Asn1 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"xs">>, {listValue, [
+            {bigIntValue, 1}, {bigIntValue, 2}, {bigIntValue, 3}
+        ]}}
+    ]}},
+    ?assertEqual(Legacy, encode(Asn1)).
+
+equivalence_tuple_field_test() ->
+    T = [{p, {int, binary}}],
+    V = [{p, {42, <<"hi">>}}],
+    Legacy = gmser_chain_objects:serialize(account, 1, T, V),
+
+    Asn1 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"p">>, {tupleValue, [
+            {bigIntValue, 42}, {binaryValue, <<"hi">>}
+        ]}}
+    ]}},
+    ?assertEqual(Legacy, encode(Asn1)).
+
+equivalence_signed_tx_concrete_test() ->
+    T = [{signatures, [binary]}, {tx, binary}],
+    V = [{signatures, [<<"sig1">>, <<"sig2">>]}, {tx, <<"txbody123">>}],
+    Legacy = gmser_chain_objects:serialize(signed_tx, 1, T, V),
+
+    Asn1 = {'GajumaruData', 11, 1, {signedTx, {'SignedTx',
+        [<<"sig1">>, <<"sig2">>], <<"txbody123">>}}},
+    ?assertEqual(Legacy, encode(Asn1)).
+
+equivalence_list_of_tuples_test() ->
+    %% Corresponds to type_info style: list of 4-tuples
+    T = [{type_info, [{binary, binary, binary, binary}]}],
+    V = [{type_info, [
+        {<<"h1">>, <<"n1">>, <<"a1">>, <<"o1">>},
+        {<<"h2">>, <<"n2">>, <<"a2">>, <<"o2">>}
+    ]}],
+    Legacy = gmser_chain_objects:serialize(account, 1, T, V),
+
+    Asn1 = {'GajumaruData', 10, 1, {templateFields, [
+        {'TemplateField', <<"type_info">>, {listValue, [
+            {tupleValue, [{binaryValue,<<"h1">>},{binaryValue,<<"n1">>},
+                          {binaryValue,<<"a1">>},{binaryValue,<<"o1">>}]},
+            {tupleValue, [{binaryValue,<<"h2">>},{binaryValue,<<"n2">>},
+                          {binaryValue,<<"a2">>},{binaryValue,<<"o2">>}]}
+        ]}}
+    ]}},
+    ?assertEqual(Legacy, encode(Asn1)).
+
+equivalence_contract_v3_test() ->
+    T = [ {source_hash, binary}
+        , {type_info, [{binary, binary, bool, binary, binary}]}
+        , {byte_code, binary}
+        , {compiler_version, binary}
+        , {payable, bool}
+        ],
+    TI = [{<<"h">>, <<"n">>, true, <<"a">>, <<"o">>}],
+    V = [ {source_hash, <<"hash">>}
+        , {type_info, TI}
+        , {byte_code, <<"code">>}
+        , {compiler_version, <<"vsn">>}
+        , {payable, true}
+        ],
+    Legacy = gmser_chain_objects:serialize(contract, 3, T, V),
+
+    Asn1 = {'GajumaruData', 40, 3, {contract, {v3, {'ContractV3',
+        <<"hash">>,
+        [ {<<"h">>, <<"n">>, true, <<"a">>, <<"o">>} ],
+        <<"code">>,
+        <<"vsn">>,
+        true
+    }}}},
+    ?assertEqual(Legacy, encode(Asn1)).
+
+-endif.
@@ -13,6 +13,8 @@
 -export([ serialize/4
        , deserialize/4
        , deserialize_type_and_vsn/1
+        , tag/1
+        , rev_tag/1
        ]).

 -type template() :: gmserialization:template().
@@ -34,8 +36,14 @@ deserialize_type_and_vsn(Binary) ->
 deserialize(Type, Vsn, Template, Binary) ->
    gmserialization:deserialize(Type, tag(Type), Vsn, Template, Binary).

+%% Numeric wire tag for a chain-object type atom (e.g. spend_tx -> 12).
+-spec tag(atom()) -> non_neg_integer().
+
+%% Inverse of tag/1.
+-spec rev_tag(non_neg_integer()) -> atom().
+
 %%%===================================================================
-%%% Internal functions
+%%% Tag registry
 %%%===================================================================

 tag(account) -> 10;
@@ -100,6 +108,8 @@ tag(ac_deposit_tx) -> 94;
 tag(ac_update_cops_tx) -> 95;
 tag(ac_rollup_tx) -> 96;
 tag(ac_proposal_tx) -> 97;
+tag(ac_receipt) -> 98;
+tag(ac_acct_state) -> 99;
 tag(key_block) -> 100;
 tag(micro_block) -> 101;
 tag(light_micro_block) -> 102;
@@ -115,7 +125,16 @@ tag(entry) -> 140;
 tag(entry_create_tx) -> 141;
 tag(entry_transfer_tx) -> 142;
 tag(entry_destroy_tx) -> 143;
-tag(pof) -> 200.
+tag(account_key_store) -> 144;
+tag(account_create_tx) -> 145;
+tag(account_sig_store) -> 146;
+tag(auth_tx) -> 147;
+tag(proposal_gossip_tx) -> 148;
+tag(account_auth_update_tx) -> 149;
+tag(pof) -> 200;
+%% Gajumaru AC side transactions
+tag(ac_side_withdraw_tx) -> 300;
+tag(ac_side_rollup_tx) -> 301.

 rev_tag(10) -> account;
 rev_tag(11) -> signed_tx;
@@ -179,6 +198,8 @@ rev_tag(94)  -> ac_deposit_tx;
 rev_tag(95)  -> ac_update_cops_tx;
 rev_tag(96)  -> ac_rollup_tx;
 rev_tag(97)  -> ac_proposal_tx;
+rev_tag(98)  -> ac_receipt;
+rev_tag(99)  -> ac_acct_state;
 rev_tag(100) -> key_block;
 rev_tag(101) -> micro_block;
 rev_tag(102) -> light_micro_block;
@@ -194,4 +215,13 @@ rev_tag(140) -> entry;
 rev_tag(141) -> entry_create_tx;
 rev_tag(142) -> entry_transfer_tx;
 rev_tag(143) -> entry_destroy_tx;
-rev_tag(200) -> pof.
+rev_tag(144) -> account_key_store;
+rev_tag(145) -> account_create_tx;
+rev_tag(146) -> account_sig_store;
+rev_tag(147) -> auth_tx;
+rev_tag(148) -> proposal_gossip_tx;
+rev_tag(149) -> account_auth_update_tx;
+rev_tag(200) -> pof;
+%% Gajumaru AC side transactions
+rev_tag(300) -> ac_side_withdraw_tx;
+rev_tag(301) -> ac_side_rollup_tx.
@@ -14,6 +14,9 @@
        , specialize/1
        , specialize/2
        , specialize_type/1
+        , is_account/1
+        , account_pubkey/1
+        , to_map/1
        , is_id/1
        ]).

@@ -29,12 +32,17 @@
            , val
            }).

-type tag() :: 'account'
+-type subtype() :: 0..6.
+-type id_map() :: #{ type := simple_tag()
+                   , subtype => subtype()
+                   , value := binary() }.
+
+-type tag() :: {'account', subtype()} | simple_tag().
+-type simple_tag() :: 'account'
                    | 'associate_chain'
                    | 'channel'
                    | 'commitment'
                    | 'contract'
-             | 'contract_source'
                    | 'name'
                    | 'native_token'
                    | 'entry'.
@@ -57,7 +65,8 @@
                           ___TAG___ =:= contract;
                           ___TAG___ =:= channel;
                           ___TAG___ =:= associate_chain;
-                           ___TAG___ =:= entry 
+                           ___TAG___ =:= entry;
+                           ___TAG___ =:= native_token
       ).
 -define(IS_VAL(___VAL___), byte_size(___VAL___) =:= 32).

@@ -69,6 +78,8 @@
 create(Tag, Val) when ?IS_TAG(Tag), ?IS_VAL(Val) ->
    #id{ tag = Tag
       , val = Val};
+create({account,I}, Val) when is_binary(Val), I >= 0, I =< 6 ->
+    #id{ tag = {account, I}, val = Val};
 create(Tag, Val) when ?IS_VAL(Val) ->
    error({illegal_tag, Tag});
 create(Tag, Val) when ?IS_TAG(Tag)->
@@ -78,28 +89,66 @@ create(Tag, Val) ->


 -spec specialize(id()) -> {tag(), val()}.
+specialize(#id{tag = {Tag,_}, val = Val}) ->
+    {Tag, Val};
 specialize(#id{tag = Tag, val = Val}) ->
    {Tag, Val}.

 -spec specialize(id(), tag()) -> val().
+specialize(#id{tag = {Tag, _}, val = Val}, Tag) when is_binary(Val) ->
+    Val;
 specialize(#id{tag = Tag, val = Val}, Tag) when ?IS_TAG(Tag), ?IS_VAL(Val) ->
    Val.

 -spec specialize_type(id()) -> tag().
+specialize_type(#id{tag = {Tag, _}}) when ?IS_TAG(Tag) ->
+    Tag;
 specialize_type(#id{tag = Tag}) when ?IS_TAG(Tag) ->
    Tag.

+-spec is_account(id() | term()) -> boolean().
+is_account(#id{tag = account}) ->
+    true;
+is_account(#id{tag = {account, _}}) ->
+    true;
+is_account(_) ->
+    false.
+
+-spec account_pubkey(id()) -> val().
+account_pubkey(#id{tag = account, val = Val}) when ?IS_VAL(Val) ->
+    Val;
+account_pubkey(#id{tag = {account, _}, val = Val}) when ?IS_VAL(Val) ->
+    Val.
+
+-spec to_map(id()) -> id_map().
+to_map(#id{tag = {Tag, SubType}, val = Val}) when ?IS_TAG(Tag) ->
+    #{ type => Tag
+     , subtype => SubType
+     , value => Val };
+to_map(#id{tag = Tag, val = Val}) when ?IS_TAG(Tag) ->
+    #{ type => Tag
+     , value => Val }.
+
+
 -spec is_id(term()) -> boolean().
 is_id(#id{}) -> true;
 is_id(_) -> false.

 -spec encode(id()) -> binary().
+encode(#id{tag = {account, N}, val = Val}) when N =< 2#111_1111 ->
+    Ext = 2#1000_0000 bor N,
+    <<Ext:8, Val/binary>>;
 encode(#id{tag = Tag, val = Val}) ->
    Res = <<(encode_tag(Tag)):?TAG_SIZE/unit:8, Val/binary>>,
    true = ?SERIALIZED_SIZE =:= byte_size(Res),
    Res.

 -spec decode(binary()) -> id().
+decode(<<Ext:8, Rest/binary>>) when Ext >= 2#1000_0000 ->
+    %% Extended account id type
+    Type = Ext band 2#0111_1111,
+    #id{ tag = {account, Type}
+       , val = Rest };
 decode(<<Tag:?TAG_SIZE/unit:8, Val:?PUB_SIZE/binary>>) ->
    #id{ tag = decode_tag(Tag)
       , val = Val}.
@@ -0,0 +1,387 @@
+%%%-------------------------------------------------------------------
+%%% @copyright (C) 2026, QPQ AG
+%%% @doc
+%%% Export static serialization templates as ASN.1 type definitions.
+%%%
+%%% This is the portable schema surface for the template language in
+%%% {@link gmserialization}: given a chain-object tag, version and
+%%% field template, emit ASN.1 that other languages can compile to
+%%% typed headers. The wire format remains RLP; ASN.1 is the abstract
+%%% model, not BER/DER on the chain.
+%%%
+%%% Minimal API (discovery of all templates is left to callers):
+%%% <pre>
+%%%   Template = aec_spend_tx:serialization_template(1),
+%%%   Tag      = gmser_chain_objects:tag(spend_tx),
+%%%   {ok, Asn1} = gmser_schema_export:object_to_asn1(Tag, 1, Template).
+%%% </pre>
+%%%
+%%% Or assemble a full module from several objects:
+%%% <pre>
+%%%   gmser_schema_export:module_to_asn1(
+%%%       'GajumaruChainObjects',
+%%%       [{spend_tx, Tag, 1, Template},
+%%%        {signed_tx, 11, 1, SignedTemplate}]).
+%%% </pre>
+%%% @end
+%%%-------------------------------------------------------------------
+-module(gmser_schema_export).
+-vsn("0.1.0").
+
+-export([ object_to_asn1/3
+        , object_to_asn1/4
+        , module_to_asn1/2
+        , module_to_asn1/3
+        , write_module/3
+        , write_module/4
+        , type_name/2
+        , type_name/3
+        ]).
+
+-export_type([ object_spec/0
+             , export_opts/0
+             ]).
+
+-type template() :: gmserialization:template().
+-type type_name() :: atom() | string() | binary().
+
+%% {Tag, Vsn, Template} | {TypeName, Tag, Vsn, Template}
+-type object_spec() ::
+      {non_neg_integer(), non_neg_integer(), template()}
+    | {type_name(), non_neg_integer(), non_neg_integer(), template()}.
+
+-type export_opts() ::
+        #{ type_name => type_name()
+         , include_tag_vsn => boolean()  %% default true
+         }.
+
+%%%===================================================================
+%%% API
+%%%===================================================================
+
+%% @doc Emit ASN.1 type definitions for one object (no module wrapper).
+-spec object_to_asn1(non_neg_integer(), non_neg_integer(), template()) ->
+          {ok, TypeName :: string(), Defs :: iodata()}.
+object_to_asn1(Tag, Vsn, Template) ->
+    object_to_asn1(Tag, Vsn, Template, #{}).
+
+-spec object_to_asn1(non_neg_integer(), non_neg_integer(), template(),
+                     export_opts()) ->
+          {ok, TypeName :: string(), Defs :: iodata()}.
+object_to_asn1(Tag, Vsn, Template, Opts) when is_map(Opts) ->
+    assert_template(Template),
+    TypeName = case maps:get(type_name, Opts, undefined) of
+                   undefined -> type_name(Tag, Vsn);
+                   Name      -> normalize_type_name(Name, Vsn)
+               end,
+    IncludeTagVsn = maps:get(include_tag_vsn, Opts, true),
+    Fields = case IncludeTagVsn of
+                 true ->
+                     [{tag, {fixed_int, Tag}},
+                      {vsn, {fixed_int, Vsn}}
+                      | Template];
+                 false ->
+                     Template
+             end,
+    {ok, Body} = emit_sequence(TypeName, Fields),
+    {ok, TypeName, Body}.
+
+%% @doc Emit a complete ASN.1 module for a list of objects.
+-spec module_to_asn1(type_name(), [object_spec()]) -> {ok, iodata()}.
+module_to_asn1(ModuleName, Objects) ->
+    module_to_asn1(ModuleName, Objects, #{}).
+
+-spec module_to_asn1(type_name(), [object_spec()], export_opts()) ->
+          {ok, iodata()}.
+module_to_asn1(ModuleName, Objects, Opts) when is_list(Objects), is_map(Opts) ->
+    Mod = asn1_type_name(ModuleName),
+    {TypeParts, IndexLines} =
+        lists:mapfoldl(
+          fun(Spec, Acc) ->
+                  {Tag, Vsn, Template, NameOpt} = expand_spec(Spec),
+                  ObjOpts = case NameOpt of
+                                undefined -> Opts;
+                                N -> Opts#{type_name => N}
+                            end,
+                  {ok, TN, Defs} = object_to_asn1(Tag, Vsn, Template, ObjOpts),
+                  Index = io_lib:format(
+                            "-- tag ~w vsn ~w -> ~s~n", [Tag, Vsn, TN]),
+                  {[Defs, $\n], [Index | Acc]}
+          end,
+          [],
+          Objects),
+    Header = [
+        "-- Generated by gmser_schema_export.\n",
+        "-- Abstract syntax for static gmserialization templates.\n",
+        "-- Wire encoding remains RLP (see gmser_rlp / gmserialization);\n",
+        "-- this module is for portable types / codegen, not BER on-chain.\n",
+        "\n",
+        Mod, " DEFINITIONS\n",
+        "    AUTOMATIC TAGS ::=\n",
+        "BEGIN\n",
+        "\n",
+        "EXPORTS ALL;\n",
+        "\n",
+        common_types(),
+        "\n",
+        "-- ============================================================\n",
+        "-- Generated object types\n",
+        "-- ============================================================\n",
+        "\n"
+    ],
+    Index = [
+        "-- ============================================================\n",
+        "-- Tag / version index\n",
+        "-- ============================================================\n",
+        lists:reverse(IndexLines),
+        "\n"
+    ],
+    Footer = "END\n",
+    {ok, [Header, TypeParts, Index, Footer]}.
+
+%% @doc Write a complete ASN.1 module to a file.
+-spec write_module(file:filename(), type_name(), [object_spec()]) ->
+          ok | {error, term()}.
+write_module(Filename, ModuleName, Objects) ->
+    write_module(Filename, ModuleName, Objects, #{}).
+
+-spec write_module(file:filename(), type_name(), [object_spec()],
+                   export_opts()) ->
+          ok | {error, term()}.
+write_module(Filename, ModuleName, Objects, Opts) ->
+    {ok, Iodata} = module_to_asn1(ModuleName, Objects, Opts),
+    file:write_file(Filename, Iodata).
+
+%% @doc Derive an ASN.1 type name from tag and version.
+%% Uses {@link gmser_chain_objects:rev_tag/1} when the tag is registered,
+%% otherwise `Object{Tag}V{Vsn}`.
+-spec type_name(non_neg_integer(), non_neg_integer()) -> string().
+type_name(Tag, Vsn) ->
+    Base =
+        try gmser_chain_objects:rev_tag(Tag) of
+            Atom when is_atom(Atom) -> atom_to_list(Atom)
+        catch
+            error:function_clause ->
+                "Object" ++ integer_to_list(Tag);
+            error:{case_clause, _} ->
+                "Object" ++ integer_to_list(Tag)
+        end,
+    normalize_type_name(Base, Vsn).
+
+-spec type_name(type_name(), non_neg_integer(), non_neg_integer()) -> string().
+type_name(Name, _Tag, Vsn) ->
+    normalize_type_name(Name, Vsn).
+
+%%%===================================================================
+%%% Spec expansion
+%%%===================================================================
+
+expand_spec({Tag, Vsn, Template})
+  when is_integer(Tag), is_integer(Vsn), is_list(Template) ->
+    {Tag, Vsn, Template, undefined};
+expand_spec({Name, Tag, Vsn, Template})
+  when is_integer(Tag), is_integer(Vsn), is_list(Template) ->
+    {Tag, Vsn, Template, Name};
+expand_spec(Other) ->
+    error({bad_object_spec, Other}).
+
+%%%===================================================================
+%%% Template → ASN.1 SEQUENCE
+%%%===================================================================
+
+emit_sequence(TypeName, Fields) ->
+    Lines =
+        [io_lib:format("~s ::= SEQUENCE {~n", [TypeName])] ++
+        field_lines(Fields) ++
+        ["}\n"],
+    {ok, Lines}.
+
+field_lines([]) ->
+    [];
+field_lines([{Name, Type}]) ->
+    [io_lib:format("    ~s ~s~n",
+                   [asn1_field_name(Name), type_to_asn1(Type)])];
+field_lines([{Name, Type} | Rest]) ->
+    [io_lib:format("    ~s ~s,~n",
+                   [asn1_field_name(Name), type_to_asn1(Type)])
+     | field_lines(Rest)].
+
+%% Map one template type term to an ASN.1 type expression (string/iodata).
+type_to_asn1(int)      -> "BigInt";
+type_to_asn1(uint128)  -> "Uint128";
+type_to_asn1(uint64)   -> "Uint64";
+type_to_asn1(uint32)   -> "Uint32";
+type_to_asn1(uint16)   -> "Uint16";
+type_to_asn1(uint8)    -> "Uint8";
+type_to_asn1(bool)     -> "BOOLEAN";
+type_to_asn1(binary)   -> "OCTET STRING";
+type_to_asn1(id)       -> "Id";
+type_to_asn1({fixed_int, N}) when is_integer(N), N >= 0 ->
+    io_lib:format("INTEGER (~w)", [N]);
+type_to_asn1([ElemType]) ->
+    %% SEQUENCE OF T  (list of any length)
+    io_lib:format("SEQUENCE OF ~s", [type_to_asn1(ElemType)]);
+type_to_asn1(Type) when is_tuple(Type) ->
+    %% Fixed-arity tuple → anonymous SEQUENCE with c1..cN
+    Types = tuple_to_list(Type),
+    Components =
+        lists:map(
+          fun({I, T}) ->
+                  io_lib:format("~sc~w ~s",
+                                [indent_spacer(), I, type_to_asn1(T)])
+          end,
+          lists:zip(lists:seq(1, length(Types)), Types)),
+    ["SEQUENCE {\n",
+     join_components(Components),
+     "\n    }"];
+type_to_asn1(#{items := Items}) when is_list(Items) ->
+    %% Static map / record: named fields, order preserved, no keys on wire
+    Components =
+        [io_lib:format("~s~s ~s",
+                       [indent_spacer(),
+                        asn1_field_name(Name),
+                        type_to_asn1(T)])
+         || {Name, T} <- Items],
+    ["SEQUENCE {\n",
+     join_components(Components),
+     "\n    }"];
+type_to_asn1(Other) ->
+    error({unsupported_template_type, Other}).
+
+indent_spacer() ->
+    "        ".
+
+join_components([]) ->
+    "";
+join_components([C]) ->
+    C;
+join_components([C | Rest]) ->
+    [C, ",\n", join_components(Rest)].
+
+%%%===================================================================
+%%% Naming
+%%%===================================================================
+
+%% "spend_tx" / spend_tx / <<"spend_tx">> + vsn 1 -> "SpendTxV1"
+normalize_type_name(Name, Vsn) when is_atom(Name) ->
+    normalize_type_name(atom_to_list(Name), Vsn);
+normalize_type_name(Name, Vsn) when is_binary(Name) ->
+    normalize_type_name(binary_to_list(Name), Vsn);
+normalize_type_name(Name, Vsn) when is_list(Name), is_integer(Vsn), Vsn >= 0 ->
+    Base = asn1_type_name(Name),
+    %% Avoid double-appending version if caller already passed SpendTxV1
+    case lists:suffix("V" ++ integer_to_list(Vsn), Base) of
+        true  -> Base;
+        false -> Base ++ "V" ++ integer_to_list(Vsn)
+    end.
+
+%% Upper camel case, strip non alphanumerics: spend_tx -> SpendTx
+asn1_type_name(Name) when is_atom(Name) ->
+    asn1_type_name(atom_to_list(Name));
+asn1_type_name(Name) when is_binary(Name) ->
+    asn1_type_name(binary_to_list(Name));
+asn1_type_name(Name) when is_list(Name) ->
+    Parts = split_name(Name),
+    lists:flatten([uppercase_first(P) || P <- Parts, P =/= ""]).
+
+%% Field names: lower camel case (ASN.1 values start with lowercase;
+%% hyphens/underscores avoided for Java friendliness).
+asn1_field_name(Name) when is_atom(Name) ->
+    asn1_field_name(atom_to_list(Name));
+asn1_field_name(Name) when is_binary(Name) ->
+    asn1_field_name(binary_to_list(Name));
+asn1_field_name(Name) when is_list(Name) ->
+    case split_name(Name) of
+        [] ->
+            error({bad_field_name, Name});
+        [First | Rest] ->
+            lists:flatten([lowercase_first(First)
+                           | [uppercase_first(P) || P <- Rest, P =/= ""]])
+    end.
+
+split_name(Name) ->
+    %% Split on '_' or '-'
+    split_name(Name, [], []).
+
+split_name([], Acc, Cur) ->
+    lists:reverse(case Cur of
+                      [] -> Acc;
+                      _  -> [lists:reverse(Cur) | Acc]
+                  end);
+split_name([C | Rest], Acc, Cur) when C =:= $_; C =:= $- ->
+    case Cur of
+        [] -> split_name(Rest, Acc, []);
+        _  -> split_name(Rest, [lists:reverse(Cur) | Acc], [])
+    end;
+split_name([C | Rest], Acc, Cur) ->
+    split_name(Rest, Acc, [C | Cur]).
+
+uppercase_first([C | Rest]) when C >= $a, C =< $z ->
+    [C - ($a - $A) | Rest];
+uppercase_first(Other) ->
+    Other.
+
+lowercase_first([C | Rest]) when C >= $A, C =< $Z ->
+    [C + ($a - $A) | Rest];
+lowercase_first(Other) ->
+    Other.
+
+%%%===================================================================
+%%% Common ASN.1 types (shared vocabulary)
+%%%===================================================================
+
+common_types() ->
+    "-- ============================================================\n"
+    "-- Common types (gmserialization template vocabulary)\n"
+    "-- ============================================================\n"
+    "\n"
+    "Id ::= SEQUENCE {\n"
+    "    type  INTEGER (0..255),\n"
+    "    value OCTET STRING (SIZE (32))\n"
+    "}\n"
+    "\n"
+    "-- Non-negative bignum (template type 'int', e.g. Pucks amounts)\n"
+    "BigInt  ::= INTEGER (0..MAX)\n"
+    "\n"
+    "Uint8   ::= INTEGER (0..255)\n"
+    "Uint16  ::= INTEGER (0..65535)\n"
+    "Uint32  ::= INTEGER (0..4294967295)\n"
+    "Uint64  ::= INTEGER (0..18446744073709551615)\n"
+    "Uint128 ::= INTEGER (0..340282366920938463463374607431768211455)\n"
+    "\n".
+
+%%%===================================================================
+%%% Validation
+%%%===================================================================
+
+assert_template(Template) when is_list(Template) ->
+    lists:foreach(
+      fun({Name, Type}) when is_atom(Name) ->
+              assert_type(Type);
+         (Other) ->
+              error({bad_template_field, Other})
+      end,
+      Template);
+assert_template(Other) ->
+    error({bad_template, Other}).
+
+assert_type(int) -> ok;
+assert_type(uint128) -> ok;
+assert_type(uint64) -> ok;
+assert_type(uint32) -> ok;
+assert_type(uint16) -> ok;
+assert_type(uint8) -> ok;
+assert_type(bool) -> ok;
+assert_type(binary) -> ok;
+assert_type(id) -> ok;
+assert_type([T]) -> assert_type(T);
+assert_type(T) when is_tuple(T) ->
+    lists:foreach(fun assert_type/1, tuple_to_list(T));
+assert_type(#{items := Items}) when is_list(Items) ->
+    lists:foreach(
+      fun({Name, T}) when is_atom(Name) -> assert_type(T);
+         (Other) -> error({bad_map_item, Other})
+      end,
+      Items);
+assert_type(Other) ->
+    error({unsupported_template_type, Other}).
@@ -29,7 +29,12 @@

 -type template() :: [{field_name(), type()}].
 -type field_name() :: atom().
-type type() :: 'int'
+-type type() :: 'int'        % bignum (non-negative, arbitrary size; used for Pucks amounts etc. up to 10^30)
+              | 'uint128'
+              | 'uint64'
+              | 'uint32'
+              | 'uint16'
+              | 'uint8'
              | 'bool'
              | 'binary'
              | 'id'     %% As defined in aec_id.erl
@@ -118,6 +123,16 @@ encode_field(#{items := Items}, Map) ->
 encode_field(Type, T) when tuple_size(Type) =:= tuple_size(T) ->
    Zipped = lists:zip(tuple_to_list(Type), tuple_to_list(T)),
    [encode_field(X, Y) || {X, Y} <- Zipped];
+encode_field(uint128, X) when is_integer(X), X >= 0, X < (1 bsl 128) ->
+    binary:encode_unsigned(X);
+encode_field(uint64, X) when is_integer(X), X >= 0, X < (1 bsl 64) ->
+    binary:encode_unsigned(X);
+encode_field(uint32, X) when is_integer(X), X >= 0, X < (1 bsl 32) ->
+    binary:encode_unsigned(X);
+encode_field(uint16, X) when is_integer(X), X >= 0, X < (1 bsl 16) ->
+    binary:encode_unsigned(X);
+encode_field(uint8, X) when is_integer(X), X >= 0, X < (1 bsl 8) ->
+    binary:encode_unsigned(X);
 encode_field(int, X) when is_integer(X), X >= 0 ->
    binary:encode_unsigned(X);
 encode_field(binary, X) when is_binary(X) -> X;
@@ -141,6 +156,31 @@ decode_field(#{items := Items}, List) when length(List) =:= length(Items) ->
 decode_field(Type, List) when length(List) =:= tuple_size(Type) ->
    Zipped = lists:zip(tuple_to_list(Type), List),
    list_to_tuple([decode_field(X, Y) || {X, Y} <- Zipped]);
+decode_field(uint128, X) when is_binary(X) ->
+    I = binary:decode_unsigned(X),
+    if I < (1 bsl 128) -> I;
+       true -> error({illegal, uint128, X})
+    end;
+decode_field(uint64, X) when is_binary(X) ->
+    I = binary:decode_unsigned(X),
+    if I < (1 bsl 64) -> I;
+       true -> error({illegal, uint64, X})
+    end;
+decode_field(uint32, X) when is_binary(X) ->
+    I = binary:decode_unsigned(X),
+    if I < (1 bsl 32) -> I;
+       true -> error({illegal, uint32, X})
+    end;
+decode_field(uint16, X) when is_binary(X) ->
+    I = binary:decode_unsigned(X),
+    if I < (1 bsl 16) -> I;
+       true -> error({illegal, uint16, X})
+    end;
+decode_field(uint8, X) when is_binary(X) ->
+    I = binary:decode_unsigned(X),
+    if I < (1 bsl 8) -> I;
+       true -> error({illegal, uint8, X})
+    end;
 decode_field(int, <<0:8, X/binary>> = B) when X =/= <<>> ->
    error({illegal, int, B});
 decode_field(int, X) when is_binary(X) -> binary:decode_unsigned(X);
@@ -194,7 +194,16 @@ known_types() ->
    Forms = get_forms(),
    [{type, _, union, Types}] =
        [Def || {attribute, _, type, {known_type, Def, []}} <- Forms],
-    [Name || {atom,_, Name} <- Types].
+    lists:flatmap(fun known_type_entry/1, Types).
+
+known_type_entry({atom, _, Name}) ->
+    [Name];
+known_type_entry({type, _, tuple,
+                  [{atom, _, account_pubkey},
+                   {type, _, range, [{integer, _, Lo}, {integer, _, Hi}]}]}) ->
+    [{account_pubkey, N} || N <- lists:seq(Lo, Hi)];
+known_type_entry(Other) ->
+    error({unsupported_known_type, Other}).

 mapped_prefixes() ->
    Forms = get_forms(),
@@ -0,0 +1,44 @@
+-module(gmser_id_tests).
+
+-include_lib("eunit/include/eunit.hrl").
+
+-define(PUBKEY, <<12345:32/unit:8>>).
+
+is_account_test() ->
+    {"is_account recognizes standard and extended account ids",
+     fun() ->
+             ?assert(gmser_id:is_account(gmser_id:create(account, ?PUBKEY))),
+             ?assert(gmser_id:is_account(gmser_id:create({account, 0}, ?PUBKEY))),
+             ?assert(gmser_id:is_account(gmser_id:create({account, 5}, ?PUBKEY))),
+             ?assertNot(gmser_id:is_account(gmser_id:create(contract, ?PUBKEY))),
+             ?assertNot(gmser_id:is_account(not_an_id))
+     end}.
+
+account_pubkey_test() ->
+    {"account_pubkey returns the 32-byte account hash",
+     fun() ->
+             ?assertEqual(?PUBKEY,
+                          gmser_id:account_pubkey(gmser_id:create(account, ?PUBKEY))),
+             ?assertEqual(?PUBKEY,
+                          gmser_id:account_pubkey(gmser_id:create({account, 3}, ?PUBKEY))),
+             ?assertEqual(?PUBKEY,
+                          gmser_id:account_pubkey(gmser_id:create({account, 6}, ?PUBKEY)))
+     end}.
+
+account_pubkey_matches_specialize_test() ->
+    {"account_pubkey agrees with specialize/2 for account ids",
+     fun() ->
+             Id = gmser_id:create({account, 2}, ?PUBKEY),
+             ?assertEqual(gmser_id:specialize(Id, account),
+                          gmser_id:account_pubkey(Id))
+     end}.
+
+extended_account_roundtrip_test() ->
+    {"extended account ids round-trip through encode/decode",
+     fun() ->
+             Id = gmser_id:create({account, 4}, ?PUBKEY),
+             ?assert(gmser_id:is_account(Id)),
+             Id1 = gmser_id:decode(gmser_id:encode(Id)),
+             ?assertEqual(?PUBKEY, gmser_id:account_pubkey(Id1)),
+             ?assertEqual(account, gmser_id:specialize_type(Id1))
+     end}.
@@ -0,0 +1,185 @@
+%%%-------------------------------------------------------------------
+%%% @copyright (C) 2026, QPQ AG
+%%% @doc
+%%% EUnit tests for gmser_schema_export.
+%%% @end
+%%%-------------------------------------------------------------------
+-module(gmser_schema_export_tests).
+
+-include_lib("eunit/include/eunit.hrl").
+
+%% Spend template as in aec_spend_tx (kept local so tests do not
+%% depend on aecore).
+spend_template() ->
+    [ {sender_id, id}
+    , {recipient_id, id}
+    , {amount, int}
+    , {gas_price, int}
+    , {gas, int}
+    , {ttl, int}
+    , {nonce, int}
+    , {payload, binary}
+    ].
+
+signed_tx_template() ->
+    [ {signatures, [binary]}
+    , {transaction, binary}
+    ].
+
+name_update_v1_template() ->
+    [ {account_id, id}
+    , {nonce, int}
+    , {name_id, id}
+    , {name_ttl, int}
+    , {pointers, [{binary, id}]}
+    , {client_ttl, int}
+    , {gas_price, int}
+    , {gas, int}
+    , {ttl, int}
+    ].
+
+match(Bin, Re) when is_binary(Bin) ->
+    re:run(Bin, Re, [{capture, none}]).
+
+%%%===================================================================
+%%% Naming
+%%%===================================================================
+
+type_name_from_registered_tag_test() ->
+    Tag = gmser_chain_objects:tag(spend_tx),
+    ?assertEqual(12, Tag),
+    ?assertEqual("SpendTxV1", gmser_schema_export:type_name(Tag, 1)).
+
+type_name_from_atom_test() ->
+    ?assertEqual("SpendTxV1",
+                 gmser_schema_export:type_name(spend_tx, 12, 1)),
+    ?assertEqual("SignedTxV1",
+                 gmser_schema_export:type_name(<<"signed_tx">>, 11, 1)).
+
+type_name_unknown_tag_test() ->
+    ?assertEqual("Object9999V2", gmser_schema_export:type_name(9999, 2)).
+
+%%%===================================================================
+%%% Single object export
+%%%===================================================================
+
+spend_object_export_test() ->
+    Tag = gmser_chain_objects:tag(spend_tx),
+    {ok, "SpendTxV1", Defs} =
+        gmser_schema_export:object_to_asn1(Tag, 1, spend_template()),
+    Text = iolist_to_binary(Defs),
+    ?assertEqual(match, match(Text, <<"SpendTxV1 ::= SEQUENCE \\{">>)),
+    ?assertEqual(match, match(Text, <<"tag INTEGER \\(12\\)">>)),
+    ?assertEqual(match, match(Text, <<"vsn INTEGER \\(1\\)">>)),
+    ?assertEqual(match, match(Text, <<"senderId Id">>)),
+    ?assertEqual(match, match(Text, <<"recipientId Id">>)),
+    ?assertEqual(match, match(Text, <<"amount BigInt">>)),
+    ?assertEqual(match, match(Text, <<"gasPrice BigInt">>)),
+    ?assertEqual(match, match(Text, <<"payload OCTET STRING">>)),
+    %% last field must not have a trailing comma before closing brace
+    ?assertEqual(match, match(Text, <<"payload OCTET STRING\n}">>)).
+
+spend_without_tag_vsn_fields_test() ->
+    Tag = gmser_chain_objects:tag(spend_tx),
+    {ok, "SpendTxV1", Defs} =
+        gmser_schema_export:object_to_asn1(
+          Tag, 1, spend_template(), #{include_tag_vsn => false}),
+    Text = iolist_to_binary(Defs),
+    ?assertEqual(nomatch, match(Text, <<"tag INTEGER">>)),
+    ?assertEqual(match, match(Text, <<"senderId Id">>)).
+
+explicit_type_name_test() ->
+    {ok, "MySpendV1", Defs} =
+        gmser_schema_export:object_to_asn1(
+          12, 1, spend_template(), #{type_name => "MySpend"}),
+    Text = iolist_to_binary(Defs),
+    ?assertEqual(match, match(Text, <<"MySpendV1 ::= SEQUENCE">>)).
+
+%%%===================================================================
+%%% Nested types
+%%%===================================================================
+
+list_and_tuple_export_test() ->
+    Tag = gmser_chain_objects:tag(name_update_tx),
+    {ok, TypeName, Defs} =
+        gmser_schema_export:object_to_asn1(Tag, 1, name_update_v1_template()),
+    ?assertEqual("NameUpdateTxV1", TypeName),
+    Text = iolist_to_binary(Defs),
+    ?assertEqual(match, match(Text, <<"pointers SEQUENCE OF SEQUENCE \\{">>)),
+    ?assertEqual(match, match(Text, <<"c1 OCTET STRING">>)),
+    ?assertEqual(match, match(Text, <<"c2 Id">>)).
+
+signed_tx_list_field_test() ->
+    Tag = gmser_chain_objects:tag(signed_tx),
+    {ok, "SignedTxV1", Defs} =
+        gmser_schema_export:object_to_asn1(Tag, 1, signed_tx_template()),
+    Text = iolist_to_binary(Defs),
+    ?assertEqual(match, match(Text, <<"signatures SEQUENCE OF OCTET STRING">>)),
+    ?assertEqual(match, match(Text, <<"transaction OCTET STRING">>)).
+
+map_items_export_test() ->
+    Template = [{body, #{items => [{foo, int}, {bar, binary}]}}],
+    {ok, _, Defs} =
+        gmser_schema_export:object_to_asn1(
+          10, 1, Template, #{type_name => account, include_tag_vsn => false}),
+    Text = iolist_to_binary(Defs),
+    ?assertEqual(match, match(Text, <<"body SEQUENCE \\{">>)),
+    ?assertEqual(match, match(Text, <<"foo BigInt">>)),
+    ?assertEqual(match, match(Text, <<"bar OCTET STRING">>)).
+
+uint_types_export_test() ->
+    Template = [{a, uint8}, {b, uint16}, {c, uint32},
+                {d, uint64}, {e, uint128}, {f, bool}],
+    {ok, _, Defs} =
+        gmser_schema_export:object_to_asn1(
+          1, 1, Template,
+          #{type_name => "Uints", include_tag_vsn => false}),
+    Text = iolist_to_binary(Defs),
+    ?assertEqual(match, match(Text, <<"a Uint8">>)),
+    ?assertEqual(match, match(Text, <<"b Uint16">>)),
+    ?assertEqual(match, match(Text, <<"c Uint32">>)),
+    ?assertEqual(match, match(Text, <<"d Uint64">>)),
+    ?assertEqual(match, match(Text, <<"e Uint128">>)),
+    ?assertEqual(match, match(Text, <<"f BOOLEAN">>)).
+
+%%%===================================================================
+%%% Full module
+%%%===================================================================
+
+module_export_test() ->
+    Objects =
+        [ {spend_tx,
+           gmser_chain_objects:tag(spend_tx),
+           1,
+           spend_template()}
+        , {gmser_chain_objects:tag(signed_tx), 1, signed_tx_template()}
+        ],
+    {ok, Iodata} =
+        gmser_schema_export:module_to_asn1('GajumaruChainObjects', Objects),
+    Text = iolist_to_binary(Iodata),
+    ?assertEqual(match, match(Text, <<"GajumaruChainObjects DEFINITIONS">>)),
+    ?assertEqual(match, match(Text, <<"Id ::= SEQUENCE">>)),
+    ?assertEqual(match, match(Text, <<"BigInt  ::= INTEGER">>)),
+    ?assertEqual(match, match(Text, <<"SpendTxV1 ::= SEQUENCE">>)),
+    ?assertEqual(match, match(Text, <<"SignedTxV1 ::= SEQUENCE">>)),
+    ?assertEqual(match, match(Text, <<"tag 12 vsn 1 -> SpendTxV1">>)),
+    ?assertEqual(match, match(Text, <<"tag 11 vsn 1 -> SignedTxV1">>)),
+    ?assertEqual(match, re:run(Text, <<"^END">>, [{capture, none}, multiline])).
+
+write_module_test() ->
+    Tmp = filename:join(
+            filename:basedir(user_cache, "gmser_schema_export"),
+            "gmser_schema_export_test.asn"),
+    ok = filelib:ensure_dir(Tmp),
+    Objects =
+        [{gmser_chain_objects:tag(spend_tx), 1, spend_template()}],
+    ?assertEqual(ok, gmser_schema_export:write_module(
+                       Tmp, 'GajumaruChainObjects', Objects)),
+    {ok, Bin} = file:read_file(Tmp),
+    ?assertEqual(match, match(Bin, <<"SpendTxV1 ::= SEQUENCE">>)),
+    ok = file:delete(Tmp).
+
+bad_template_test() ->
+    ?assertError({unsupported_template_type, float},
+                 gmser_schema_export:object_to_asn1(
+                   1, 1, [{x, float}])).
Author	SHA1	Message	Date
Ulf Wiger	b2e9af0acb	Add ASN.1 schema export from static serialization templates. Gajumaru Serialization Tests / tests (push) Successful in 48m24s Details Introduce gmser_schema_export to emit portable ASN.1 type definitions from tag/version/template triples (RLP remains the wire format). Export tag/1 and rev_tag/1 for discovery and naming, with docs and eunit coverage.	2026-07-22 11:26:49 +02:00
Ulf Wiger	4036133476	Updated asn1 experiment, now exploring PER and OER Gajumaru Serialization Tests / tests (push) Successful in 12s Details	2026-07-08 10:53:31 +02:00
Ulf Wiger	9817af8a46	Add thin ASN.1-driven RLP production layer + equivalence tests Gajumaru Serialization Tests / tests (push) Successful in 10s Details Implements gmser_asn1_rlp:encode/1 that accepts terms shaped according to the GajumaruSerialization.asn model (e.g. GajumaruData with templateFields or concrete CHOICEs like signedTx) and emits exactly the same RLP bytes as the legacy gmserialization + gmser_rlp stack. Purpose: - Use ASN.1 as a formal, multi-language friendly schema and type model. - Provide a thin, portable "production layer" that other languages can implement (ASN.1-generated types + equivalent RLP emitter). - Preserve the existing compact RLP wire format and on-the-wire equivalence (no DER bloat for the legacy path). The implementation walks the ASN.1-shaped value and applies the same encoding rules as gmserialization:encode_field/2 (minimal unsigned integers, positional values for static maps, etc.) followed by gmser_rlp:encode/1. Includes EUnit equivalence tests covering: - Simple fields, zero/empty values - Lists and tuples - List-of-tuples (e.g. type_info) - Concrete signedTx - ContractV3 (including bool in structured data) All tests assert byte-for-byte identity with legacy serialization and that the resulting bytes are still accepted by legacy decoders. This continues the proof-of-concept on the uw-asn1 branch.	2026-07-07 10:48:30 +02:00
Ulf Wiger	6d7ab1e4ad	PoC: ASN.1 / DER serialization experiment Gajumaru Serialization Tests / tests (push) Successful in 10s Details This branch contains a proof-of-concept exploration of representing the RLP (gmser_rlp) and gmserialization layers using ASN.1 with DER encoding. Goals of the experiment: - Model the static serialization templates and dynamic types in ASN.1. - Demonstrate reliable detection of legacy RLP data vs. new DER data (first byte >= 0xC0 for RLP lists vs. 0x30 for DER SEQUENCE). - Evaluate wire-size overhead of standard DER TLV encoding compared to the extremely compact RLP prefix encoding. - Verify that the DER path produces deterministic output suitable for hashing (idempotent serialization). Key files: - GajumaruSerialization.asn -- the ASN.1 schema - GajumaruSerialization.{erl,hrl} -- generated encoder/decoder - detect_demo.erl, size_comparison.erl -- supporting test code Findings (high level): - Detection via first byte works cleanly. - DER is fully deterministic for hashing when the same value is given. - Small objects pay a significant size overhead (often 3-6x) due to TLV tags/lengths and field names in the generic path. - Concrete SEQUENCE definitions are much more compact than the generic templateFields representation. - Large payloads have acceptable relative overhead. This is NOT production code. It was created to answer feasibility questions around ASN.1 modeling, format detection, determinism, and size characteristics. Branch created from uw-new-acs for isolated experimentation.	2026-07-07 10:05:30 +02:00
Ulf Wiger	c80505c810	Fix ac_acct_state tag and restore key_block mapping Gajumaru Serialization Tests / tests (push) Successful in 11s Details The previous commit accidentally removed key_block (tag 100) instead of adding ac_acct_state (tag 99).	2026-07-07 08:13:37 +02:00
Ulf Wiger	0e157f824a	Add ac_acct_state serialization tag Gajumaru Serialization Tests / tests (push) Successful in 10s Details	2026-07-07 08:07:58 +02:00
Ulf Wiger	faa20bd00b	Add ac_receipt and AC side tx tags from `ac793dcaf6` Gajumaru Serialization Tests / tests (push) Successful in 12s Details Cherry-pick the chain-object tags from `ac793dcaf6` while keeping the extended-auth account types (account_sig_store, auth_tx, etc.).	2026-07-06 22:27:28 +02:00
Ulf Wiger	79b43b0665	Add account_auth_update_tx tag Gajumaru Serialization Tests / tests (push) Successful in 11s Details	2026-07-06 15:30:19 +02:00
Ulf Wiger	a84dcc880d	Add is_account/1 and account_pubkey/1 helpers Gajumaru Serialization Tests / tests (push) Successful in 11s Details Extended-auth account ids use an {account, Subtype} tag. These helpers let callers test account membership and extract the 32-byte pubkey without pattern-matching on specialize/1 results.	2026-07-06 12:26:38 +02:00
Ulf Wiger	a368c64f7e	Add missing tag for proposal_gossip_tx Gajumaru Serialization Tests / tests (push) Successful in 11s Details	2026-07-06 10:55:20 +02:00
Ulf Wiger	dbfc013c8a	Add auth tx and account sig store Gajumaru Serialization Tests / tests (push) Successful in 11s Details	2026-07-06 10:19:38 +02:00
Ulf Wiger	7a8e840793	Add support for extended-auth account types Gajumaru Serialization Tests / tests (push) Successful in 11s Details	2026-07-05 08:38:42 +02:00