MD5加密與解密

public static string MD5Encrypt(string pToEncrypt)//加密
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.GetBytes(pToEncrypt);
            byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定義偏移量  （可自定義）
            byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定義密鑰（可自定義）
            des.Key = key;
            des.IV = iv;
            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);
            }
            return ret.ToString();
            byte[] bytResult = ms.ToArray();
            string strResult = BitConverter.ToString(bytResult);
            strResult = strResult.Replace("-", "");
            return strResult;
        }

        public static string MD5Decrypt(string pToDecrypt)//解密
        {
            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;
            }
            byte[] iv = { 102, 16, 93, 156, 78, 4, 218, 32 };//定義偏移量（可自定義對應解密）
            byte[] key = { 55, 103, 246, 79, 36, 99, 167, 3 };//定義密鑰（可自定義對應解密）
            des.Key = key;
            des.IV = iv;
            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());
        }