OAuth2 : Verifying the ADFS JWT signature

I wrote up this post recently: OAuth2 : Verifying the Azure AD JWT signature.

So how do you do this with ADFS? You need ADFS 4.0 - Server 2016.

This has the following ADFS OAuth information ( ~ metadata) endpoints:

https://my-adfs/adfs/.well-known/openid-configuration

https://my-adfs/adfs/discovery/keys

https://my-adfs/adfs/userinfo

If we go to the "keys" endpoint, we see:

{
  "keys": [
    {
      "kty": "RSA",
      "use": "sig",
      "alg": "RS256",
      "kid": "hHk-...A6k",
      "x5t": "hHk-...A6k",
      "n": "tGy...w9Q",
      "e": "AQAB",
      "x5c": [
        "MIIC7..Log=="
      ]
    }
  ]
}

The information under "x5c" is the certificate that you need.

As  per the linked post, you need to wrap this with "---BEGIN--- ---END---" and copy / paste and you'll see that the signing key is now verified.

Enjoy!