JWT SecurityTokenInvalidSignatureException using RS256 PII is hidden

You can increase your Key length as shown below in appsettings.json file.

"Jwt": {
    "Key": "pintusharmaqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqweqwe",
    "Issuer": "pintusharma.com"
  }

It turns out that the KeySize for X509SecurityKey needs to be at least 1024 in length for verifying. This is not obvious from the exception, since it is hidden with the [PII is hidden] filter.

Adding the following line made the exception text a lot more useful (add to ConfigureServices method in Startup.cs):

IdentityModelEventSource.ShowPII = true;

The new exception text:

'System.ArgumentOutOfRangeException: IDX10631: The 'Microsoft.IdentityModel.Tokens.X509SecurityKey' for verifying cannot be smaller than '1024' bits. KeySize: '512'.

Increasing the length of the assymetric key to 1024 solved the problem.