對稱可逆加密Des

加密後能解密回原文,但是需要一個key

加密key與解密key是一樣的(對稱)

但是key的安全性問題一定要得到保證

code:

        //key可以寫在配置文件中
        //加密key 
        static string key = "A1B2C3D4E5";
        private static byte[] _rgbKey = ASCIIEncoding.ASCII.GetBytes(key.Substring(0, 8));
        //解密key
        private static byte[] _rgbIV = ASCIIEncoding.ASCII.GetBytes(key.Insert(0, "w").Substring(0, 8));

        /// <summary>
        /// DES加密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public async Task<string> Encrypt(string str)
        {
            var dsp = new DESCryptoServiceProvider();
            //創建一個流對象
            using (MemoryStream stream = new MemoryStream())
            {
                //將數據寫入流中
                CryptoStream cryptoStream = new CryptoStream(stream, dsp.CreateEncryptor(_rgbKey, _rgbIV),
                    CryptoStreamMode.Write);
                StreamWriter streamWriter = new StreamWriter(cryptoStream);
                streamWriter.Write(str);
                streamWriter.Flush();
                cryptoStream.FlushFinalBlock();
                stream.Flush();
                return Convert.ToBase64String(stream.GetBuffer(), 0, (int)stream.Length);
            }
        }

        /// <summary>
        /// DES解密
        /// </summary>
        /// <param name="str"></param>
        /// <returns></returns>
        public async Task<string> Decrypt(string str)
        {
            var dsp = new DESCryptoServiceProvider();
            byte[] buffer = Convert.FromBase64String(str);
            using (MemoryStream stream = new MemoryStream())
            {
                CryptoStream cryptoStream = new CryptoStream(stream, dsp.CreateEncryptor(_rgbKey, _rgbIV), CryptoStreamMode.Write);
                cryptoStream.Write(buffer, 0, buffer.Length);
                cryptoStream.FlushFinalBlock();
                return Encoding.UTF8.GetString(stream.ToArray());
            }
        }