Spring OAuth2 with JWT - Cannot convert access token to JSON When Separating Auth and Resource Servers

Question

I am looking to use Spring Boot to create an OAuth2 Authentication server that could be used by multiple Resource server. Consequently, I am needing to create the two server

Answer 1

First you must verify if the JWT is using asymmetric key or symmetric key. As @Child said, setVerifierKey will be used when an asymmetric key is used for encryption.

Second, make sure PublicKey has been encoded to string in the correct way:

import java.security.PublicKey;
import java.util.Base64;

PublicKey publicKey = getPublicKey();
String strPublicKey = Base64.getEncoder().encodeToString(publicKey.getEncoded());`

Third, make sure that the string-key passed to the setVerifierKey is formatted as below (you can test it here):

String verifierKey = String.format("-----BEGIN PUBLIC KEY-----\n%s\n-----END PUBLIC KEY-----", strPublicKey);
converter.setVerifierKey(verifierKey);

If in doubt, I recommend this article.