Add ML-DSA-65 and ML-DSA-87 certificate parsing and verification - #312
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justsem wants to merge 2 commits into
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Add ML-DSA-65 and ML-DSA-87 certificate parsing and verification#312justsem wants to merge 2 commits into
justsem wants to merge 2 commits into
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Motivation: The upcoming ML-DSA support uses the MLDSA65/MLDSA87 APIs that first appeared in swift-crypto 4.0.0. Raising the floor in a minor release follows this repository's own precedent (apple#39, apple#275, apple#300). A SwiftPM trait was considered instead, but traits are used in the ecosystem to gate optional dependencies, not versions of a required one, and SE-0450 cannot express a per-trait version floor. Modifications: - Raise the swift-crypto lower bound from 3.12.3 to 4.0.0 in Package.swift and Benchmarks/Package.swift. Result: swift-certificates requires swift-crypto 4.0.0 or later, which dependency resolution already selects for any graph that does not pin swift-crypto below 4.
Motivation: RFC 9881 registers algorithm identifiers for ML-DSA (FIPS 204) in X.509, and swift-crypto ships MLDSA65 and MLDSA87. swift-certificates could not even parse a certificate whose issuer signed with ML-DSA: Certificate.init threw on the issuer's signature algorithm before any verification was attempted, blocking post-quantum CA hierarchies. Modifications: - Add the id-ml-dsa-65 and id-ml-dsa-87 OIDs and AlgorithmIdentifier statics (parameters absent, per RFC 9881), and Certificate.SignatureAlgorithm.mldsa65/.mldsa87. - Extend Certificate.Signature with a backing case carrying the raw signature bytes, mirroring Ed25519. - Add MLDSA.swift: ML-DSA public keys are stored as validated raw bytes and rebuilt per verification, because CryptoKit's ML-DSA types are macOS 26+ on Darwin and enum cases cannot carry availability. Below macOS 26 an ML-DSA subject public key fails loudly at decode; on Linux support is unconditional. - Extend Certificate.PublicKey with SPKI decode/encode, verification dispatch, and the standard wrap/unwrap initializers. - Add MLDSATests with OpenSSL 3.6.3 interop fixtures covering parse, byte-identical round-trips, self-signature known-answer tests, tampered/wrong-parameter-set/wrong-root/padding-bits negatives, ML-DSA-44 rejection, and chain validation through Verifier with RFC5280Policy. Signing, ML-DSA-44, HashML-DSA, and TLS signature-scheme codepoints are deliberately not supported and throw unsupportedSignatureAlgorithm. Result: Certificates signed with ML-DSA-65 or ML-DSA-87 parse, round-trip, and verify, including full chains through the normal verifier path.
Joannis
reviewed
Aug 11, 2026
| .package(path: "../"), | ||
| .package(url: "https://github.com/ordo-one/benchmark.git", from: "1.11.1"), | ||
| .package(url: "https://github.com/apple/swift-crypto.git", "3.12.3"..<"5.0.0"), | ||
| .package(url: "https://github.com/apple/swift-crypto.git", "4.0.0"..<"5.0.0"), |
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I was discussing using a package trait to avoid needing this, let us know what works.
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CC @fabianfett if you're back, could we get a CI run on this? |
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swift-certificates can't yet parse a certificate signed with ML-DSA: it throws on the issuer's signature algorithm before verification even starts, even though swift-crypto already supports these algorithms. That turned out to be a blocker in one of our projects involving PQ PKI.
This PR adds parsing and verification for ML-DSA-65 and ML-DSA-87, per RFC 9881.