Move MLDsa Experimental to appropriate members

[bartonjs]

Not experimental:

• MLDsaAlgorithm (whole type)
• MLDsa (class name)
• MLDsa.GenerateKey
• MLDsa.ImportMLDsaPublicKey
• MLDsa.ImportMLDsaPrivateKey
• MLDsa.ImportMLDsaPrivateSeed
• MLDsa.ExportMLDsaPublicKey
• MLDsa.ExportMLDsaPrivateKey
• MLDsa.ExportMLDsaPrivateSeed
• MLDsa.SignData
• MLDsa.VerifyData
• Any *Core method for the above
• CngAlgorithm.MLDsa
• CngAlgorithmGroup.MLDsa
• CngBlobFormat.PQDsaPublicBlob
• CngBlobFormat.PQDsaPrivateBlob
• CngBlobFormat.PQDsaPrivateSeedBlob

Experimental:

• IETF Formats
  • MLDsa.ImportFromPem
  • MLDsa.ImportFromEncryptedPem
  • MLDsa.ImportPkcs8PrivateKey
  • MLDsa.ImportEncryptedPkcs8PrivateKey
  • MLDsa.ImportSubjectPublicKeyInfo
  • MLDsa.ExportPkcs8PrivateKey
  • MLDsa.ExportPkcs8PrivateKeyPem
  • MLDsa.ExportEncryptedPkcs8PrivateKey
  • MLDsa.ExportEncryptedPkcs8PrivateKeyPem
  • MLDsa.ExportSubjectPublicKeyInfo
  • MLDsa.ExportSubjectPublicKeyInfoPem
  • And any related Try* or *Core methods
• Unsure we have the right shape
  • MLDsa.SignPreHash
  • MLDsa.VerifyPreHash
  • MLDsa.SignMu
  • MLDsa.VerifyMu
  • And any *Core methods powering them

[Copilot]

Pull Request Overview

This PR removes the experimental attribute from the base MLDsa class and MLDsaAlgorithm type while adding the experimental attribute to specific members that are still considered experimental. The primary purpose is to graduate core ML-DSA functionality from experimental status while keeping IETF format methods and certain signing methods as experimental.

• Removes [Experimental] attribute from the base MLDsa class and MLDsaAlgorithm type
• Adds [Experimental] attribute to specific IETF format import/export methods
• Adds [Experimental] attribute to PreHash and Mu signing/verification methods

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/libraries/System.Security.Cryptography/ref/System.Security.Cryptography.cs	Updates reference assembly to move experimental attributes from class level to specific IETF and PreHash/Mu methods
src/libraries/Common/src/System/Security/Cryptography/MLDsaAlgorithm.cs	Removes experimental attribute from the MLDsaAlgorithm class
src/libraries/Common/src/System/Security/Cryptography/MLDsa.cs	Removes experimental attribute from MLDsa class and adds it to specific IETF format and PreHash/Mu methods

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[bartonjs]

I sanity checked this by adding a quick and dirty test to a library that doesn't already have global suppressions enabled:

private static byte[] Sign(byte[] key, byte[] message)
{
    using (MLDsa mldsa = MLDsa.ImportMLDsaPrivateSeed(MLDsaAlgorithm.MLDsa44, key))
    {
        return mldsa.SignData(message);
    }
}

No warnings.
Then:

-       return mldsa.SignData(message);
+       return mldsa.SignMu(message);

And SYSLIB5006 was correctly emitted.

[vcsjones]

What about the derived types? MLDsaCng and MLDsaOpenSsl? When we did MLKem we also removed it from the whole class on the derived types and some of the "helper" stuff like CngAlgorithm and CngAlgorithmGroup.

[vcsjones]

Here's the MLKem PR for reference. #117831

[bartonjs]

What about the derived types?

Whoops.

some of the "helper" stuff like CngAlgorithm and CngAlgorithmGroup

CngAlgorithm and CngAlgorithmGroup I'm pretty solid on. The CngBlobFormats I also did, but I feel less good about... if I were Windows I'd be regretting the "PQ" name and trying to replace it before full GA... but I don't expect them to, so I went ahead and removed it.

If anyone wants to be hesitant on the PQ blobs, I'm happy to put it back. They're not really important for mainline usage.

[vcsjones]

If anyone wants to be hesitant on the PQ blobs, I'm happy to put it back. They're not really important for mainline usage.

I paused and thought about it. But yeah I think I am least concerned about these.

[vcsjones]

@bartonjs why does this need API review?

[bartonjs]

why does this need API review?

It changes the ref.cs file. And no one is answering email 😄