C#中DES加密解密

加密和解密是一门高深和复杂的学科。在程序中有时需要用一些简单的加密和解密，以保证一些关键字符串、值等地安全性。这里就要用到DES加密解密。当然我们不用深究这些加密的原理了，因为如果深究的话估计都得转行研究数学。DES加密解密C#中需要用到这几个类，DESCryptoServiceProvider，CryptoStream。

看下面的两组加密解密代码。

1、

       （1）、对字符串进行DES加密

        public static string Encrypt(string sourceString, string key, string iv)
        {
            try
            {
                byte[] btKey = Encoding.UTF8.GetBytes(key);

                byte[] btIV = Encoding.UTF8.GetBytes(iv);

                DESCryptoServiceProvider des = new DESCryptoServiceProvider();

                using (MemoryStream ms = new MemoryStream())
                {
                    byte[] inData = Encoding.UTF8.GetBytes(sourceString);
                    try
                    {
                        using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(btKey, btIV), CryptoStreamMode.Write))
                        {
                            cs.Write(inData, 0, inData.Length);

                            cs.FlushFinalBlock();
                        }

                        return Convert.ToBase64String(ms.ToArray());
                    }
                    catch
                    {
                        return sourceString;
                    }
                }
            }
            catch { }

            return "DES加密出错";
        }
调用：
            string recordString = Encrypt("金胖子死了", "20111219", "12345678");
结果：recordString= "xQ969nexy964SXhkTuekUQ=="

（2）、 对DES加密后的字符串进行解密

        public static string Decrypt(string encryptedString, string key, string iv)
        {
            byte[] btKey = Encoding.UTF8.GetBytes(key);

            byte[] btIV = Encoding.UTF8.GetBytes(iv);

            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            using (MemoryStream ms = new MemoryStream())
            {
                byte[] inData = Convert.FromBase64String(encryptedString);
                try
                {
                    using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(btKey, btIV), CryptoStreamMode.Write))
                    {
                        cs.Write(inData, 0, inData.Length);

                        cs.FlushFinalBlock();
                    }

                    return Encoding.UTF8.GetString(ms.ToArray());
                }
                catch
                {
                    return encryptedString;
                }
            }
        }
调用：string recordString = DESOperation.Decrypt("xQ969nexy964SXhkTuekUQ==", "20111219", "12345678");
结果：recordString = “金胖子死了”;

2、

  （1）、加密字符串

        public static string EncryptString(string sInputString, string sKey, string sIV)
        {
            try
            {
                byte[] data = Encoding.UTF8.GetBytes(sInputString);

                DESCryptoServiceProvider DES = new DESCryptoServiceProvider();

                DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);

                DES.IV = ASCIIEncoding.ASCII.GetBytes(sIV);

                ICryptoTransform desencrypt = DES.CreateEncryptor();

                byte[] result = desencrypt.TransformFinalBlock(data, 0, data.Length);

                return BitConverter.ToString(result);
            }
            catch { }

            return "转换出错！";
        }
调用：string recordString = DESOperation.EncryptString("金胖子死了", "20111219", "12345678");
结果：recordString = "C5-0F-7A-F6-77-B1-CB-DE-B8-49-78-64-4E-E7-A4-51";

（2）、解密字符串

        public static string DecryptString(string sInputString, string sKey, string sIV)
        {
            try
            {
                string[] sInput = sInputString.Split("-".ToCharArray());

                byte[] data = new byte[sInput.Length];

                for (int i = 0; i < sInput.Length; i++)
                {
                    data[i] = byte.Parse(sInput[i], NumberStyles.HexNumber);
                }

                DESCryptoServiceProvider DES = new DESCryptoServiceProvider();

                DES.Key = ASCIIEncoding.ASCII.GetBytes(sKey);

                DES.IV = ASCIIEncoding.ASCII.GetBytes(sIV);

                ICryptoTransform desencrypt = DES.CreateDecryptor();

                byte[] result = desencrypt.TransformFinalBlock(data, 0, data.Length);

                return Encoding.UTF8.GetString(result);
            }
            catch { }

            return "解密出错！";
        }
调用：string recordString = DESOperation.DecryptString("C5-0F-7A-F6-77-B1-CB-DE-B8-49-78-64-4E-E7-A4-51", "20111219", "12345678");
结果：recordString =” 金胖子死了”;

注意：密钥和向量必须为8位，否则加密解密都不成功。