title: Jose4j validate signature alg RS256 against encryption algorithm
body: <p>The JWT is signed with RS256, and I am using jose4j to verify JWT signature. In one of user environment which I do not have access, it generates this unexpected exception:</p>
  
  <blockquote>
    <p>org.jose4j.lang.InvalidAlgorithmException: RS256 is an unknown,
    unsupported or unavailable alg algorithm (not one of [RSA1_5,
    RSA-OAEP, RSA-OAEP-256, dir, A128KW, A192KW, A256KW, ECDH-ES,
    ECDH-ES+A128KW, ECDH-ES+A192KW, ECDH-ES+A256KW, PBES2-HS256+A128KW,
    PBES2-HS384+A192KW, PBES2-HS512+A256KW, A128GCMKW, A192GCMKW,
    A256GCMKW])</p>
  </blockquote>
  
  <p>Looks like the signature algorithm is incorrectly validated against Key encryption algorithm. Note that my codes only do signature validation, and do not have any logic for decryption/encryption. This only happens in one user environment, and I can not access or recreate it locally. </p>
  
  <p>Does anyone ever see such a problem? or can give me a hint to debug it?</p>