C#SM4加密算法

1.管理NuGet程序包，搜索BouncyCastle，安装

2.代码示例

//加密算法：SM4
//加密模式：ECB
//填充模式：PKCS5Padding
//编码类型：UTF-8

        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="plainText"></param>
        /// <param name="secretKey"></param>
        /// <returns></returns>
        public string MS4Encrypt_ECB(string plainText, string secretKey)
        {
            byte[] plaintext = Encoding.UTF8.GetBytes(plainText);
            byte[] keyBytes = Encoding.UTF8.GetBytes(secretKey);
            IBufferedCipher inCipher = CipherUtilities.GetCipher("SM4/ECB/PKCS5Padding");
            KeyParameter key = ParameterUtilities.CreateKeyParameter("SM4", keyBytes);
            inCipher.Init(true, key);
            byte[] cipher = inCipher.DoFinal(plaintext);
            //加密结果数据格式Hex
            byte[] encrypted2 = Hex.Encode(cipher);
            return Encoding.UTF8.GetString(encrypted2).ToUpper();
 
        }
      
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="cipherText"></param>
        /// <param name="secretKey"></param>
        /// <returns></returns>
        public string MS4Decrypt_ECB(string cipherText, string secretKey)
        {
            byte[] keyBytes = Encoding.UTF8.GetBytes(secretKey);
            byte[] plaintext = Encoding.UTF8.GetBytes(cipherText);
            IBufferedCipher inCipher = CipherUtilities.GetCipher("SM4/ECB/PKCS5Padding");
            KeyParameter key = ParameterUtilities.CreateKeyParameter("SM4", keyBytes);
            var cipher = Hex.Encode(plaintext);
            inCipher.Reset();
            inCipher.Init(false, key);
            byte[] bin = inCipher.DoFinal(cipher);
            string ans = Encoding.UTF8.GetString(bin);
            return ans;
        }
       // 当secretKey为Base64位字符串，使用ECB加密为Base64

         public static string MS4Encrypt_ECB(string plainText, string secretKey)
         {
                    byte[] keyBytes = Convert.FromBase64String(secretKey);
                    byte[] plaintext = Encoding.UTF8.GetBytes(plainText);
                    IBufferedCipher inCipher = CipherUtilities.GetCipher("SM4/ECB/PKCS5Padding");
                    KeyParameter key = ParameterUtilities.CreateKeyParameter("SM4", keyBytes);
                    inCipher.Init(true, key);
                    byte[] cipher = inCipher.DoFinal(plaintext);
                    return Convert.ToBase64String(cipher);

        }

在线工具:https://lzltool.cn/SM4