Module integrity 

FEP-8b32 Object Integrity Proof verification (eddsa-jcs-2022 and mldsa44-jcs-2024).

Fedify-based servers (GoToSocial, hackers.pub, …) attach a Data Integrity proof to the activities they deliver, authenticating the activity itself rather than the HTTP transport. This lets a recipient accept an activity whose HTTP Signature it can’t verify (a different signature spec, a shared inbox, or a forwarded/relayed delivery) as long as the author’s proof holds.

The algorithm mirrors Fedify’s verifyProof (packages/fedify/src/sig/proof.ts) and the W3C “Data Integrity EdDSA Cryptosuites” eddsa-jcs-2022 suite:

1. proofConfig = the document’s @context plus the fixed proof metadata (type, cryptosuite, verificationMethod, proofPurpose, created).
2. unsecuredDocument = the activity with every proof form removed.
3. hashData = SHA-256(JCS(proofConfig)) ‖ SHA-256(JCS(unsecuredDocument)).
4. Verify the proofValue over hashData with the key resolved from the proof’s verificationMethod.

mldsa44-jcs-2024 (W3C “Verifiable Credential Data Integrity — Quantum Resistant Cryptosuites”) is the same algorithm over ML-DSA-44 instead of Ed25519, with one deliberate difference in step 1 that the specification itself calls out: the proof configuration always takes the document’s @context, rather than keeping whatever the proof carried.

Enums

Cryptosuite

The cryptosuites this module can verify.

PublicKey

A public key resolved from a proof’s verificationMethod.

Constants

DATA_INTEGRITY_CONTEXT

The Data Integrity context that defines proof, version 1: what a document is to carry before a proof is attached to it, for a JSON-LD reader to find the proof at all.

Functions

decode_ed25519_multikey

Decode a Multikey publicKeyMultibase value into a raw 32-byte Ed25519 key.

decode_mldsa44_multikey

Decode a Multikey publicKeyMultibase value into an ML-DSA-44 public key.

decode_multikey

Decode whichever key type a Multikey carries.

ed25519_public_key

The public key of a raw 32-byte Ed25519 seed.

encode_ed25519_multikey

The Multikey publicKeyMultibase for an Ed25519 public key: the ed25519-pub multicodec header, base58btc, with multibase’s z prefix.

extract_integrity_proof

Find a usable assertion-method integrity proof on document, if present, and not expired at now, in seconds since the Unix epoch.

generate_ed25519_key

Generate an Ed25519 signing key, returned as a PKCS#8 PEM.

generate_ed25519_seed

A fresh raw 32-byte Ed25519 seed.

integrity_proofs

Every usable assertion-method integrity proof on document, in order, as extract_integrity_proof returns one. A document may carry several, in different suites or by different keys, and one that does not verify says nothing about the others.

parse_ed25519_key

The raw 32-byte seed and public key of a PKCS#8 PEM Ed25519 key.

sign_object_integrity_proof

Attach an eddsa-jcs-2022 integrity proof to document.

verify_object_integrity_proof

Verify an integrity proof on document against public_key, the key resolved from the proof’s verificationMethod.

with_data_integrity_context

document with DATA_INTEGRITY_CONTEXT in its @context, however that is shaped — added to an array, made an array with a single context, or set when there is none — and as it was if it is there already. None when document is not an object.