DES加密深度优化——随机生成加密字符串

DES全称为Data Encryption Standard，即数据加密标准，是一种使用密钥加密的块算法。但该算法一旦密钥固定，加密的字符串也就随之固定，这不利于数据存储安全。而且用该方法加密后有一个显著的标记，末位几位为‘=’。所有本次优化对密钥和去等进行了一些优化。

首先我们生成8位随机字符串作为加密的key值。

  private static string so = "1234567890abcdefghijklmnopqrstuvwxyzQWERTYUIOPASDFGHJKLZXCVBNM";



        /// <summary>

        /// 生成内容随机key

        /// </summary>

        /// <returns></returns>

        public static string GetContent()

        {

            Random rand = new Random();

            string str = null;

            for (int i = 0; i < 8; i++)

            {

                str += so.Substring(rand.Next(62), 1);

            }

            return str;

        }

然后将key值进行拆分为两部分。

   Random rand = new Random();

                int r = rand.Next(9);

                string encryptKey = GetContent();

                string first = encryptKey.Substring(0, r);

                string last = encryptKey.Substring(r);

最后对需加密的字符串进行DES加密，并记录等号的个数并截取去除等号字符串，然后与key值左右部分拼接。

    private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

        /// <summary> 

        /// DES加密字符串 

        /// </summary> 

        /// <param name="encryptString">待加密的字符串</param> 

        /// <returns>加密成功返回加密后的字符串，失败返回源串</returns> 

        public static string Encrypt(string encryptString)

        {

            try

            {

                Random rand = new Random();

                int r = rand.Next(9);

                string encryptKey = GetContent();

                string first = encryptKey.Substring(0, r);

                string last = encryptKey.Substring(r);



                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));

                byte[] rgbIV = Keys;

                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);

                DESCryptoServiceProvider dCsp = new DESCryptoServiceProvider();

                MemoryStream mStream = new MemoryStream();

                CryptoStream cStream = new CryptoStream(mStream, dCsp.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

                cStream.Write(inputByteArray, 0, inputByteArray.Length);

                cStream.FlushFinalBlock();

                string str = Convert.ToBase64String(mStream.ToArray());

                int i = 0;

                for (int j = str.Length - 1; j > 0; j--)

                {

                    if (str[j] != '=')

                    {

                        break;

                    }

                    else

                    {

                        i++;

                    }

                }

                str = str.Substring(0, str.Length - i);

                return i.ToString()+r.ToString()+first + str +last;

            }

            catch

            {

                return encryptString;

            }

        }

对加密的字符串进行解密。

    /// <summary> 

        /// DES解密字符串 

        /// </summary> 

        /// <param name="decryptString">待解密的字符串</param> 

        /// <returns>解密成功返回解密后的字符串，失败返源串</returns> 

        public static string Decrypt(string decryptString)

        {

            try

            {

                int code = Int32.Parse(decryptString.Substring(1, 1));

                int i = Int32.Parse(decryptString.Substring(0, 1));



                string first = decryptString.Substring(2, code);

                string last = decryptString.Substring(decryptString.Length - 8 + code);

                string encryptKey =first+last;

                decryptString = decryptString.Substring(code + 2, decryptString.Length - 10);

                for (int j = 0; j < i; j++)

                {

                    decryptString += "=";

                }

                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey);

                byte[] rgbIV = Keys;

                byte[] inputByteArray = Convert.FromBase64String(decryptString);

                DESCryptoServiceProvider dcsp = new DESCryptoServiceProvider();

                MemoryStream mStream = new MemoryStream();

                CryptoStream cStream = new CryptoStream(mStream, dcsp.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);

                cStream.Write(inputByteArray, 0, inputByteArray.Length);

                cStream.FlushFinalBlock();

                return Encoding.UTF8.GetString(mStream.ToArray());

            }

            catch

            {

                return decryptString;

            }

        }

应用及演示：

   public static void Main(string[] args)

        {

            string str = "xuhang";

            for (int i = 0; i < 10; i++)

            {

                var m = DesNew.Encrypt(str);

                Console.WriteLine(m);

                Console.WriteLine(DesNew.Decrypt(m));

                Console.WriteLine("------------------------------");

                Thread.Sleep(500); //0.5s后唤醒线程，避免由于时间短生成的数据一致

            }

        }