Currently only RSA algorithms are supported. (https://github.com/wildfly-security/wildfly-elytron/blob/9ba1145096b3755526f61c9d152daada040c1b95/auth/realm/token/src/main/java/org/wildfly/security/auth/realm/token/validator/JwtValidator.java#L286-L295)

AWS ALBs issue tokens signed with ES256, which will not work with the elytron token realm.

Would be great to have support for this algorithm.