.NET Core上面的DES等加密算法要等到1.2 才支持，我们可是急需这个算法的支持，文章《使用 JavaScriptService 在.NET Core 里实现DES加密算法》需要用Nodejs，很多人觉得这个有点不好，今天就给大家介绍下BouncyCastle （Portable.BouncyCastle）https://www.nuget.org/packages/Portable.BouncyCastle/库为我们提供的原生的.NET Core的支持库的Des算法。BouncyCastle的文档比较少，折腾了好久才写出了.NET 代码等价的一个封装。

public class TDesbouncy
    {

        IBlockCipher engine = new DesEngine();

        /// <summary>
        /// 使用DES加密，key输入密码的时候，必须使用英文字符，区分大小写，且字符数量是8个，不能多也不能少
        /// </summary>
        /// <param name="plainText">需要加密的字符串</param>
        /// <param name="keys">加密字符串的密钥</param>
        /// <returns>加密后的字符串</returns>
        public string Encrypt(string keys, string plainText)
        {

            byte[] ptBytes = Encoding.UTF8.GetBytes(plainText);
            byte[] rv = Encrypt(keys, ptBytes);
            StringBuilder ret = new StringBuilder();
            foreach (byte b in rv)
            {
                ret.AppendFormat("{0:X2}", b);
            }
            return ret.ToString();
        }

        private byte[] Encrypt(string keys, byte[] ptBytes)
        {
            byte[] key = Encoding.UTF8.GetBytes(keys);
            BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(new CbcBlockCipher(engine),new Pkcs7Padding());
            cipher.Init(true, new ParametersWithIV(new DesParameters(key),key));
            byte[] rv = new byte[cipher.GetOutputSize(ptBytes.Length)];
            int tam = cipher.ProcessBytes(ptBytes, 0, ptBytes.Length, rv, 0);

             cipher.DoFinal(rv, tam);
             return rv;
        }

        /// <summary>
        /// 使用DES解密，key输入密码的时候，必须使用英文字符，区分大小写，且字符数量是8个，不能多也不能少
        /// </summary>
        /// <param name="cipherText">需要加密的字符串</param>
        /// <param name="keys">加密字符串的密钥</param>
        /// <returns>解密后的字符串</returns>
        public string Decrypt(string keys, string cipherText)
        {
            byte[] inputByteArray = new byte[cipherText.Length / 2];
            for (int x = 0; x < cipherText.Length / 2; x++)
            {
                int i = (Convert.ToInt32(cipherText.Substring(x * 2, 2), 16));
                inputByteArray[x] = (byte)i;
            }
            var rv = Decrypt(keys, inputByteArray);

            return Encoding.UTF8.GetString(rv);

        }

        private byte[] Decrypt(string keys, byte[] cipherText)
        {
            byte[] key = Encoding.UTF8.GetBytes(keys);
            BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(new CbcBlockCipher(engine));
            cipher.Init(false, new ParametersWithIV(new DesParameters(key), key));
            byte[] rv = new byte[cipher.GetOutputSize(cipherText.Length)];
            int tam = cipher.ProcessBytes(cipherText, 0, cipherText.Length, rv, 0);

            cipher.DoFinal(rv, tam);

            return rv;
        }

    }

public static void Main(string[] args)
{ 
            
            Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);

            string key = "geffzhan";
            string content =   "This project.config whoopla is a mess. So what they mean by .NetCore, you still have to reference everything correctly";

            TDesbouncy bouncy = new TDesbouncy();

            var encrypt = bouncy.Encrypt(key, content);
            Console.WriteLine(encrypt);

            string descontent = bouncy.Decrypt(key, encrypt);
            Console.WriteLine(descontent);
}

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