anchor.diff:      }
       return CURRENT;
     }
  -  
  +
     Map<String, RSAPrivateKey> iss_privateKeys = {};
     Map<String, Map<String, JWT>> _store = {};
  -     
  +
     void registerKey(String isss, String pemkey, {String password}){
       rsa_pkcs.RSAPKCSParser parser = new rsa_pkcs.RSAPKCSParser();
       rsa_pkcs.RSAPrivateKey pk = parser.parsePEM(pemkey, password:password).private;
       RSAPrivateKey privk = new RSAPrivateKey(pk.modulus, pk.privateExponent, pk.prime1, pk.prime2);
       iss_privateKeys[isss]=privk;
  -    _store[isss] = {}; 
  +    _store[isss] = {};
     }
  -  
  +
     Future<JWT> generateJWT(String isss , String scopes){
       JWT jwt;
       if (_store[isss].containsKey(scopes)){
  
positive.code:                  "exp":exp,
                   "iat":iat};
    }
    
    bool get isExpired {
      DateTime now = new DateTime.now();
      return iat >= auth["expires_in"] + (now.millisecondsSinceEpoch ~/ 1000);
    }
      
    Future generateAuth(String privateKeyFile){
      return _generateJWT(privateKeyFile).then((jwt){
        Map map = {"grant_type": "urn:ietf:params:oauth:grant-type:jwt-bearer",
  
negative.code:       return signature.bytes;
      });
    }
  
  
    String _mapToQuery(Map<String, String> map, {Encoding encoding}) {
      var pairs = <List<String>>[];
  