DES

public static class DESEncryptionUtility
    {
        public static DESCryptoServiceProvider keyProvider = new DESCryptoServiceProvider();
        //默认密钥向量
        public static byte[] Encryption2Byte(string input,byte[] key=null,byte[] iv=null)
        {
            //加密
            MemoryStream ms = new MemoryStream();
            keyProvider.Mode = CipherMode.ECB;
            keyProvider.Padding = PaddingMode.PKCS7;
            ICryptoTransform cryptoTransform = key == null ? keyProvider.CreateEncryptor() : keyProvider.CreateEncryptor(key, iv);
            //ICryptoTransform cryptoTransform = keyProvider.CreateEncryptor();
            CryptoStream encStream = new CryptoStream(ms, cryptoTransform, CryptoStreamMode.Write);
            StreamWriter sw = new StreamWriter(encStream);
            sw.WriteLine(input);
            sw.Close();
            //获取加密后的字节
            byte[] buffer = ms.ToArray();
            return buffer;
        }
        public static string Encryption(string input,string key=null,string iv=null)
        {
            byte[] buffer;
            if (key == null)
            {
                buffer = Encryption2Byte(input);
            }
            else
            {
                var bKey = Encoding.UTF8.GetBytes(key);
                var bIV = Encoding.UTF8.GetBytes(iv);
                buffer = Encryption2Byte(input, bKey,bIV);
            }
            return Convert.ToBase64String(buffer);
        }
        public static string DeEncryption2Byte(byte[] secret, byte[] key = null, byte[] iv = null)
        {
            MemoryStream ms = new MemoryStream(secret);
            keyProvider.Mode = CipherMode.ECB;
            keyProvider.Padding = PaddingMode.PKCS7;
            ICryptoTransform cryptoTransform = key == null ? keyProvider.CreateDecryptor() : keyProvider.CreateDecryptor(key, iv);
            CryptoStream encStream = new CryptoStream(ms, cryptoTransform, CryptoStreamMode.Read);
            StreamReader sr = new StreamReader(encStream);
            //输出解密后的内容
            var result = sr.ReadLine();
            keyProvider.Clear();
            sr.Close();
            return result;
        }
        public static string DeEncryption(string secret, string key = null, string iv = null)
        {
            byte[] buffer = Convert.FromBase64String(secret);
            if (key == null)
            {
                return DeEncryption2Byte(buffer);
            }
            else
            {
                var bKey = Encoding.UTF8.GetBytes(key);
                var bIV = Encoding.UTF8.GetBytes(iv);
                return DeEncryption2Byte(buffer, bKey, bIV);
            }
        }
    }

DES

原文：https://www.cnblogs.com/ives/p/des.html