For Japanese version, see ISemanticHasher-jp.md.

ISemanticHasher (Semantic Hash Interface Specification)

1. Responsibility Boundary

ISemanticHasher computes and verifies deterministic hash fingerprints representing canonical ROM semantics.

• Role:

Produce algorithm-bound deterministic digests and verify digest equality against expected values.

• Non-role:

Canonicalization itself is delegated to IRomCanonicalizer.

2. Contract Signature

namespace AIKernel.Abstractions.Rom;\n\npublic interface ISemanticHasher\n{\n    string Algorithm { get; }\n\n    string ComputeHash(CanonicalizedRomDto canonicalized);\n\n    Task<string> ComputeHashAsync(CanonicalizedRomDto canonicalized, CancellationToken cancellationToken = default);\n\n    bool VerifyHash(CanonicalizedRomDto canonicalized, string expectedHash);\n\n    Task<bool> VerifyHashAsync(\n        CanonicalizedRomDto canonicalized,\n        string expectedHash,\n        CancellationToken cancellationToken = default);\n}

3. Related Use Cases

• UC-13 Runtime signature verification and governance:

Provides digest foundation for signature payload checks.

• UC-20 Deterministic replay:

Enables fast semantic equivalence checks between runtime and stored ROM.

• UC-01 ROM load validation:

Supports integrity checks at ingestion.

4. Governance & Determinism

• Full determinism:

Same Algorithm + same CanonicalizedRomDto must yield identical hash text.

• Collision resistance:

Implementations should use modern secure hash functions to reduce semantic-collision risk.

• Algorithm consistency:

Behavior changes affecting persisted hashes require strict compatibility governance.

5. Exception Contract

This interface does not hard-code exception types. Implementations should clearly surface:

• Crypto subsystem failures:

Digest computation infrastructure errors.

• Unsupported algorithms:

Algorithm requested but unavailable in current runtime.

6. Implementation Notes

• Prefix format:

Prefer algorithm-tagged hash notation (e.g., sha256:...) for crypto agility.

• Asset-chain integrity:

Include referenced binary-asset digests in canonical payloads to preserve end-to-end integrity.

Changelog

• v0.0.0 / v0.0.0.0: Initial draft
• v0.0.1 (2026-05-06): Version upgrade aligned with documentation guidelines