public static SecretKey createKey(String encoded,String algo){
  return new SecretKeySpec(Base64.decodeBase64(encoded.getBytes(SignatureHelper.UTF_8)),algo);
}

public static SecretKey createKey ( String encoded , String algo ) { return new SecretKeySpec ( Base64 . decodeBase64 ( encoded . getBytes ( SignatureHelper . UTF_8 ) ) , algo ) ; }
creates a secretkey from encoded string
