System.InvalidOperationException: This implementation is not part of the Windows Platform FIPS validated cryptographic algorithms. at System.Security.Cryptography.SHA1Managed..ctor() at ....

When I say “learnt”, it was more about reading documents to determine what happened to cause the above error.

I suspect either of these:

1. Microsoft have released a new schannel.dll which removes and/or breaks SHA1 functionally.
2. The Group Policy setting “System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing” has been enabled.

My quick “fix” was to change the application to use a different hashing algorithm.

References:

• System cryptography: Use FIPS compliant algorithms for encryption, hashing, and signing” security setting effects in Windows XP and in later versions of Windows
• FIPS validated cryptographic algorithms in .NET
• NIST: Secure Hashing Standards Validation List
• Microsoft: FIPS 140 Validation
• Microsoft: AES Provider Algorithms

Related posts:

Microsoft breaks own application Samba–like a dog returning … Duplicate files and hashing in Visual Basic.

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