Exact

Exact Union RegExp

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Transaction Science 1a63a8d66e Identity assertions validate in the C2PA SDK's validator: the holder signs the schema's order by default, a verifier accepts either serialization ... Every identity assertion WAI wrote was reported cawg.x509.signature.mismatch by the C2PA SDK's validator. Read at their sources: Identity Assertion 1.0 to 1.3 §8.2.1 (the payload is serialized in RFC 8949 §4.2.1's core deterministic encoding and those bytes are signed; no later version or erratum), and the c2pa crate at 0.91.7 and 0.91.11, its newest release, which signs and verifies its own serialization of the payload's members in the schema's order (referenced_assertions, sig_type, role; url, alg, hash) with the writer that keeps declaration order. The bytes signed were the whole difference: the COSE structure, protected header, sig_type, hashed URIs and chain of a WAI assertion and of one the SDK's builder writes are the same. c2pa-binding §4.10, §4.11, §6.2 step 12, §6.3, §9.2, §9.3 and decisions D6 (revised): a writer signs the schema's order by default and may be asked for the core deterministic encoding (identity::Signed); the stored assertion stays deterministic either way. The verifier accepts a signature over either serialization of the payload's members, states which, and refuses one over a third order, over other members, or by another key. On the SDK's path an identity assertion is read in any well-formed encoding (one the SDK's builder wrote is accepted) and a map with a key twice is refused. Tests run the SDK's validator, configured with the corpora's anchors, on manifests signed through the SDK and on the store writer's stores beside their envelopes: trusted, no failure code, cawg.x509.credential.trusted, cawg.x509.signature.validated and cawg.identity.well-formed for each identity assertion. The strict form gets exactly cawg.x509.signature.mismatch, pinned. c2pa-sdk-identity/vectors.json pins the validator's report of every file at the SDK's version. Both corpora regenerated with their tools (c2pa-identity byte for byte on x86_64 and aarch64); new vectors for the strict form, the SDK builder's assertion, a signature over a third order and over other members. Both Python verifiers compute the two serializations themselves and are caught without either and when they take the members in any order. The wire break and the three API changes are acknowledged in the change note. Co-Authored-By: Claude Fable 5.2 <[email protected]>		2026-11-11 09:58:01 -05:00
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store.c2pa	Identity assertions validate in the C2PA SDK's validator: the holder signs the schema's order by default, a verifier accepts either serialization	2026-11-11 09:58:01 -05:00