Signing: certificate fingerprint comparisons should be case-insensitive

[dtivel]

NuGet Product(s) Affected

NuGet.exe, Visual Studio Package Management UI, Visual Studio Package Manager Console, dotnet.exe

Current Behavior

See #13114.

If you hand-edit nuget.config and copy-and-paste in a lower-case certificate fingerprint, the trusted signer feature won't work. Only if the fingerprint is upper case will it work.

Desired Behavior

Certificate fingerprints are commonly represented in hexadecimal, which is case-insensitive. We already perform case-insensitive string comparisons on certificate fingerprints here and here, but not here or critically here. (Note: this is not an exhaustive list of fingerprint comparisons.)

While hand-editing nuget.config, especially for trusted signers, is not recommended, it is frustrating to realize --- because it's undocumented, to the best of my knowledge --- that the fingerprint must be upper case.

Additional Context

No response