Sign JWT token using Azure Key Vault

Hi. Apologies if it’s bad form to link straight to my StackOverflow question - I thought I’d save on the duplication. I’m happy to copy across the content if that’s preferred.

Basically, I’m having trouble signing a JWT via Azure Key Vault. It works fine if I don’t use Azure Key Vault. I put code example and full description in the Stackovlow question…

https://stackoverflow.com/questions/69117288/sign-jwt-token-using-azure-key-vault

Environment:

• Name and version of the Library package used: Azure.Security.KeyVault.Keys 4.2.0
• Hosting platform or OS and .NET runtime version (dotnet --info output for .NET Core projects): LINQPad 6 (which I believe is .NET 5 runtime)
• IDE and version : LINQPad 6

[heaths]

Great!

FWIW, one thing I’ve learned over the years is that Windows-based APIs are often Unicode, i.e. wide chars, but industry standards more often tend to be UTF-8 based - JWTs and the family included. Encoding.UTF8 is technically correct in this case, but there’s the potential for more processing involved when, because the value is base64url-encoded, you know all the characters are ASCII already.

[dracan]

@heaths - that’s amazing, it worked! 😃 It was literally just the changing from Encoding.Unicode. to Encoding.ASCII. that fixed it for me. Amazing how a single word can cause so many problems! The public keys that I pasted into jwt.io were all -----BEGIN CERTIFICATE-----, but I think that was fine. The tokens also weren’t working against the endpoint I was trying to authenticate against either - so it wasn’t just jwt.io. Using Encoding.ASCII, it all works perfectly! Thank you so much for your help with this 😃