The method GetKeyedHashAlgorithm of InMemorySymmetricSecurityKey class with SecurityAlgorithms.HmacSha256Signature as argument throws System.NotSupportedException.
The code which creates the HMACSHA256 instance is commented out on mono master branch without any obvious reason: https://github.com/mono/mono/blob/master/mcs/class/System.IdentityModel/System.IdentityModel.Tokens/InMemorySymmetricSecurityKey.cs#L126
Also the method IsSupportedAlgorithm returns false when specifying SecurityAlgorithms.HmacSha256Signature.
HMACSHA256 is already properly supported by mono, therefore HMACSHA256 should be enabled for compatibility reasons.
Created attachment 13720 [details]
Created attachment 13721 [details]
Created attachment 13722 [details]
Proposed patch (fixed)
Just curious, why hasn't this patch been merged yet? I'm running into this issue too.
Could you please convert your test and patch into Mono Pull Request
fixed with https://github.com/mono/mono/pull/6130