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Conformance & parity

The protocol is implemented several times — the Rust producer, the host, the dig-client-wasm verifier, the DIG Browser C++, the SDK/extension JS. They stay interchangeable only because of a parity discipline: every shared constant has one definition, and frozen goldens fail the build the moment any implementation drifts.

The C8 parity invariant​

Every cryptographic constant has ONE definition shared across producer, host, and verifier. There is no per-layer reimplementation of the read-crypto: producer, host-serve, and the browser verifier all call digstore_core::crypto + digstore_core::resource_leaf (parity test dig-client-wasm/tests/parity.rs).

What every reimplementation MUST pass​

SurfaceFrozen byWhat it pins
URN canonical() + retrieval_key()digstore-core/tests/urn.rs:107-126; dighub-core recomputes SHA-256 independentlythe exact canonical-string bytes and their hash, for all four parsers
Crypto (HKDF + GCM-SIV)C8 KAT fixtures (kdf_kat.rs)a distinct (URN, salt) ⇒ a distinct 32-byte key; tag failure on wrong key
BLS host↔guesthost-signed fixtures the guest must accept (tests/bls_fixtures.rs)AugScheme cross-impl parity + the five role DSTs
Merkle leaf/proofresource_leaf shared by producer + verifierD5 leaf = SHA-256(ciphertext); D8 proof length ≤ ceil(log2 n)
dig RPCOpenRPC documents generated from the implementation, CI-diffable against live server responsesthe method set, the chunk object (incl. chunk_lens, no decoy), -32004

URN conformance vectors​

The single source of truth for all four URN parsers (core, SDK, extension, browser C++) is the frozen golden set pinning canonical() + retrieval_key(). A reimplementation conforms iff it reproduces these byte-for-byte. The dig-client-wasm SRI digest is pinned in the extension and the hub service worker, fail-closed — a mismatched client is refused.

The OpenRPC-vs-server diff​

The two OpenRPC documents (network + node) are generated from scripts/dig-spec.mjs and the error catalog is drift-gated against the prose tables on every build — so the JSON, the prose, and the source enums can never silently diverge. The intent is to CI-diff the documents against live rpc.dig.net / dig-node responses so an agent can drive the protocol without scraping prose.