C#对称加密与非对称加密

对称加密——DES

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace TGSMessage
{
    class Message
    {
        //加密
        private string Encrypt(string str, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.GetBytes(str);
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);// 密匙
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);// 初始化向量
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            var retB = Convert.ToBase64String(ms.ToArray());
            return retB;
        }

        //解密
        private string Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);
            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);
            // 如果两次密匙不一样，这一步可能会引发异常
            cs.FlushFinalBlock();
            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }


        static void Main(string[] args)
        {
            string text = "";
            string message = "Hello World,Good afternoon!";
            byte[] sKey = {1,2,3,4,5,6,7,8};
            Console.WriteLine(sKey.Length);
            string key = Encoding.ASCII.GetString(sKey);
            Console.WriteLine(key);
            for (int i = 0; i < sKey.Length; i++)
            {
                text += sKey[i].ToString();
            }
            Console.WriteLine(text);
            Message msg = new Message();
            string m = msg.Encrypt(message, text);
            Console.WriteLine(m);
            Console.WriteLine(msg.Decrypt(m, text));
        }
    }
}

非对称加密——RSA

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace TGSMessage
{
    class Message
    {
        //RSA产生密钥
        public string[] GenerateKeys()
        {
            string[] sKeys = new String[2];
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            sKeys[0] = rsa.ToXmlString(true);   //私钥
            sKeys[1] = rsa.ToXmlString(false);  //公钥
            return sKeys;
        }
        

        //RSA加密
        public string EncryptString(string sSource, string sPublicKey)
        {
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            string plaintext = sSource;                //明文
            rsa.FromXmlString(sPublicKey);             //公钥加密
            byte[] cipherbytes;                        //byte类型密文
            byte[] byteEn = rsa.Encrypt(Encoding.UTF8.GetBytes("a"), false);
            cipherbytes = rsa.Encrypt(Encoding.UTF8.GetBytes(plaintext), false);
            StringBuilder sbString = new StringBuilder();
            for (int i = 0; i < cipherbytes.Length; i++)
            {
                sbString.Append(cipherbytes[i] +",");
            }
            return sbString.ToString();
        }

        //RSA解密
        public string DecryptString(String sSource, string sPrivateKey)
        {
            RSACryptoServiceProvider rsa = new RSACryptoServiceProvider();
            rsa.FromXmlString(sPrivateKey);                  //私钥解密
            byte[] byteEn = rsa.Encrypt(Encoding.UTF8.GetBytes("a"), false);
            string[] sBytes = sSource.Split(',');
            for (int j = 0; j < sBytes.Length; j++)
            {
                if (sBytes[j] != "")
                {
                    byteEn[j] = Byte.Parse(sBytes[j]);
                }
            }
            byte[] plaintbytes = rsa.Decrypt(byteEn, false);
            return Encoding.UTF8.GetString(plaintbytes);
        }

        public static void Main(string[] args)
        {
            Message msg = new Message();
            string[] keys = msg.GenerateKeys();
            foreach(string key in keys)
            {
                Console.WriteLine(key);
            }
            string text = "你好，中国";
            string En_text = msg.EncryptString(text, keys[1]);
            string De_text = msg.DecryptString(En_text, keys[0]);
            Console.WriteLine(En_text);
            Console.WriteLine(De_text);
        }
    }
}