ML-DSA Sign/VerifyPreHash

[krwq]

Contributes to: #113502

Adds pre-hash implementation.

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[Copilot]

Pull Request Overview

This PR adds “pre-hash” signing and verification functionality for both ML-DSA and SLH-DSA by extracting the common raw sign/verify logic into shared native functions, updating the PAL layers and managed bindings, and expanding the test suite.

• Introduce pal_evp_pkey_raw_signverify for generic EVP_PKEY message pre-encoding support.
• Update SLH-DSA and ML-DSA PAL implementations to delegate their pure and pre-encoded operations to the new raw functions.
• Extend managed APIs and interop (Helpers.cs, SlhDsaOpenSsl/OpenSsl, MLDsaOpenSsl/OpenSsl, and related implementations) to expose SignPreHash and VerifyPreHash.
• Add HashInfo utility for tests and enhance existing test suites to cover the new pre-hash methods.

Reviewed Changes

Copilot reviewed 33 out of 34 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/native/libs/System.Security.Cryptography.Native/pal_evp_pkey_raw_signverify.[ch]	New generic native functions for “pure” and pre-encoded signing.
src/native/libs/System.Security.Cryptography.Native/pal_evp_pkey_slh_dsa.[ch]	Delegate SLH-DSA to the shared raw sign/verify implementation.
src/native/libs/System.Security.Cryptography.Native/pal_evp_pkey_ml_dsa.[ch]	Delegate ML-DSA pre-encoded operations to the raw implementation.
src/native/libs/System.Security.Cryptography.Native/entrypoints.c	Register new MLDsa pre-hash entrypoints.
src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/Helpers.cs	Centralize hash-OID length validation and pre-hash helper logic.
src/libraries/System.Security.Cryptography/src/.../SlhDsaOpenSsl.OpenSsl.cs	Hook up the pre-hash callbacks for SLH-DSA.
src/libraries/System.Security.Cryptography/src/.../MLDsaOpenSsl.OpenSsl.cs	Hook up the pre-hash callbacks for ML-DSA.
src/libraries/Common/tests/.../HashInfo.cs	Introduce HashInfo helper and update tests for pre-hash flows.

Comments suppressed due to low confidence (2)

src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/SlhDsaOpenSsl.OpenSsl.cs:89

• [nitpick] Add a /// <inheritdoc /> comment above this override (and similarly above VerifyPreHashCore) to maintain consistent XML documentation style.

        protected override void SignPreHashCore(ReadOnlySpan<byte> hash, ReadOnlySpan<byte> context, string hashAlgorithmOid, Span<byte> destination) =>

src/native/libs/System.Security.Cryptography.Native/pal_evp_pkey_slh_dsa.c:74

• The SLH-DSA pre-encoded functions (CryptoNative_SlhDsaSignPreEncoded and CryptoNative_SlhDsaVerifyPreEncoded) are no longer referenced by managed code and can be removed to avoid dead code.

int32_t CryptoNative_SlhDsaSignPreEncoded(EVP_PKEY *pkey,

[PranavSenthilnathan]

review

[bartonjs]

What about Windows? I believe it should be working there already...

[bartonjs]

What about Windows? I believe it should be working there already...

In particular, I believe it's "just set BCRYPT_PQDSA_PADDING_INFO.pszPrehashAlgId", which we've already defined in our copy of the struct.

[krwq]

The failures don't seem to be related to my changes - merging