Require parameters in ECPrivateKey for Composite ML-DSA

[PranavSenthilnathan]

Draft 12 of the Composite ML-DSA spec now requires the parameters to be present for ECPrivateKey. This PR implements these changes in our managed Composite ML-DSA implementation.

[Copilot]

Pull Request Overview

This PR updates the Composite ML-DSA implementation to comply with Draft 12 of the specification, which now requires parameters to be present in ECPrivateKey structures. The key change is that ECPrivateKey objects must now include curve parameters (OID) for composite ML-DSA algorithms.

• Updates ECPrivateKey generation to include required curve parameters
• Modifies validation logic to enforce parameter presence and correctness
• Updates size calculations to account for the additional parameter data

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
CompositeMLDsaManaged.cs	Updates draft specification references from version 08 to 12
CompositeMLDsaManaged.ECDsa.cs	Adds parameter validation and generation for ECPrivateKey structures
CompositeMLDsaAlgorithm.cs	Updates size calculations to include parameter overhead
CompositeMLDsaTestHelpers.cs	Updates expected key size calculations with specific values per algorithm
CompositeMLDsaFactoryTests.cs	Updates test cases to reflect new parameter requirements and validation

[jeffhandley]

Let's wait for review from @bartonjs or @vcsjones to merge, but looks good to me. This would also have my support for backporting to 10.0 GA.

/cc @artl93

[PranavSenthilnathan]

No APIs changed but, following our past convention, implementing an updated PQC draft requires a breaking change doc. Assuming we get this in for .NET 10, we can just modify dotnet/docs#48901.

[dotnet-policy-service]

Added needs-breaking-change-doc-created label because this PR has the breaking-change label.

When you commit this breaking change:

1. Create and link to this PR and the issue a matching issue in the dotnet/docs repo using the breaking change documentation template, then remove this needs-breaking-change-doc-created label.
2. Ask a committer to mail the .NET Breaking Change Notification DL.

Tagging @dotnet/compat for awareness of the breaking change.

[PranavSenthilnathan]

/ba-g #103347

[PranavSenthilnathan]

/backport to release/10.0

[github-actions]

Started backporting to release/10.0 (link to workflow run)

[github-actions]

@PranavSenthilnathan backporting to release/10.0 failed, the patch most likely resulted in conflicts. Please backport manually!

git am output

$ git am --3way --empty=keep --ignore-whitespace --keep-non-patch changes.patch

Applying: Require parameters in ECPrivateKey for Composite ML-DSA
Applying: draft 12
Applying: Add comments.
Applying: Update src/libraries/Common/src/System/Security/Cryptography/CompositeMLDsaManaged.ECDsa.cs
Applying: Fix null-conditional operator usage
Applying: Add test cases for implicit and explicit curves
error: sha1 information is lacking or useless (src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/CompositeMLDsa/CompositeMLDsaFactoryTests.cs).
error: could not build fake ancestor
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0006 Add test cases for implicit and explicit curves
Error: The process '/usr/bin/git' failed with exit code 128

Link to workflow output