code: public boolean verifyMessageSignature(String message, PublicKey publicKey) {
  
          // extract the type and signature parameters
          Map<String, String> parsed = parseJSON(message);
  
          return verifySignature(parsed, publicKey);
      }
docs: Validates the signature on a Simple Notification Service message. No
  Amazon-specific dependencies, just plain Java crypto and Jackson for
  parsing
  
  @param message
  A JSON-encoded Simple Notification Service message. Note: the
  JSON may be only one level deep.
  @param publicKey
  The Simple Notification Service public key, exactly as you'd
  see it when retrieved from the cert.
  
  @return True if the message was correctly validated, otherwise false.