code: public boolean verify(final String message, final String signature) throws EncryptionException {
        try {
           Signature sign = Signature.getInstance("SHA1withRSA");
           sign.initVerify(publicKey);
           sign.update(message.getBytes(DEFAULT_CHARSET));
           return sign.verify(Base64.decodeBase64(signature.getBytes(DEFAULT_CHARSET)));
        } catch (SignatureException | NoSuchAlgorithmException | InvalidKeyException e) {
           throw new EncryptionException("Unable to verify message: ", e);
        }
     }
docs: Verifies whether the signature matches the given message.
  
  @param message
  The original message.
  @param signature
  The signature of the message.
  @return True if and only if the signature matches the given message.
  @throws EncryptionException
  When it was not possible to verify the message signature.