docs: public String decrypt(String msgSignature, String timeStamp, String nonce, String encryptedXml) {
      // 密钥，公众账号的app corpSecret
      // 提取密文
      String cipherText = extractEncryptPart(encryptedXml);
  
      try {
        // 验证安全签名
        String signature = SHA1.gen(token, timeStamp, nonce, cipherText);
        if (!signature.equals(msgSignature)) {
          throw new RuntimeException("加密消息签名校验失败");
        }
      } catch (NoSuchAlgorithmException e) {
        throw new RuntimeException(e);
      }
  
      // 解密
      String result = decrypt(cipherText);
      return result;
    }