Improve exceptions thrown by MLKem when key types aren't available. #116590
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Tagging subscribers to this area: @dotnet/area-system-security, @bartonjs, @vcsjones |
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Pull Request Overview
This PR enhances MLKEM error handling by throwing clearer exceptions when a key or seed isn’t available, instead of surfacing low-level errors.
- Introduces
ThrowExceptionIfNoSeedandThrowExceptionIfNoDecapsulationKeyhelpers. - Adds precondition checks before export/decapsulation operations in OpenSSL and Windows implementations.
- Supplies new localized exception messages and updates tests to expect
CryptographicException.
Reviewed Changes
Copilot reviewed 7 out of 7 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/MLKemOpenSsl.OpenSsl.cs | Added checks before exporting seed/decapsulation key |
| src/libraries/System.Security.Cryptography/src/System/Security/Cryptography/MLKemImplementation.OpenSsl.cs | Added availability checks before decapsulation and exports |
| src/libraries/System.Security.Cryptography/src/Resources/Strings.resx | Added new messages for missing seed/decapsulation key |
| src/libraries/Microsoft.Bcl.Cryptography/src/Resources/Strings.resx | Added new messages for missing seed/decapsulation key |
| src/libraries/Common/tests/System/Security/Cryptography/MLKemBaseTests.cs | Switched from ThrowsAny to Throws in key-missing tests |
| src/libraries/Common/src/System/Security/Cryptography/MLKemImplementation.Windows.cs | Added checks before decrypt/export operations on Windows |
| src/libraries/Common/src/System/Security/Cryptography/MLKem.cs | Introduced helper methods to throw when seed/decap key are absent |
src/libraries/System.Security.Cryptography/src/Resources/Strings.resx
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bartonjs
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Jun 12, 2025
src/libraries/Common/src/System/Security/Cryptography/MLKemImplementation.Windows.cs
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...raries/System.Security.Cryptography/src/System/Security/Cryptography/MLKemOpenSsl.OpenSsl.cs
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bartonjs
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Jun 13, 2025
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PranavSenthilnathan
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bartonjs
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Win32 bcrypt gives us unhelpful errors for ML-KEM when certain key types are not available. For example, if you created the ML-KEM instance with an expanded decapsulation key, but you ask it for a seed. In that scenario, we are throwing an exception like:
This improves the exception to something understandable when we have enough information about the key.
Fixes #116509