/// <summary>
        /// 创建Key
        /// </summary>
        /// <returns></returns>
        public static string GenerateKey()
        {
            DESCryptoServiceProvider desCrypto = (DESCryptoServiceProvider)DESCryptoServiceProvider.Create();
            return ASCIIEncoding.ASCII.GetString(desCrypto.Key);
        }
        /// <summary>
        /// MD5加密
        /// </summary>
        /// <param name="pToEncrypt"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        public static string MD5Encrypt(string pToEncrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            StringBuilder ret = new StringBuilder();
            foreach (byte b in ms.ToArray())
            {
                ret.AppendFormat("{0:X2}", b);
            }
            ret.ToString();
            return ret.ToString();


        }

        /// <summary>
        /// MD5解密
        /// </summary>
        /// <param name="pToDecrypt"></param>
        /// <param name="sKey"></param>
        /// <returns></returns>
        public static string MD5Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();

            byte[] inputByteArray = new byte[pToDecrypt.Length / 2];
            for (int x = 0; x < pToDecrypt.Length / 2; x++)
            {
                int i = (Convert.ToInt32(pToDecrypt.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }

            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();

            StringBuilder ret = new StringBuilder();

            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }

------解决方案--------------------

你觉得可能吗？


密文为固定长度，明文长度不确定，要解密的，没有这样的算法，也没有这样的压缩方法，
建议你了解下加密，解密，压缩

我要的效果是这样的，大批量数据，加密后是固定长度（最好能小于50位的），并且能被解密的算法。
因为MD5无法被解密，DES的话长度也不能固定