RSA加密

一、RSA加密简介

RSA加密是一种非对称加密。可以在不直接传递密钥的情况下，完成解密。这能够确保信息的安全性，避免了直接传递密钥所造成的被破解的风险。是由一对密钥来进行加解密的过程，分别称为公钥和私钥。通常个人保存私钥，公钥是公开的。

二、RSA加密流程如下

1.系统生成一对密钥（公钥和私钥）

2.系统将公钥告知客户

3.客户根据收到的公钥对数据进行加密，在发送给系统

4.系统收到加密后的数据，用私钥进行解密

   public class RSA
   {
        /// <summary>
        /// 生成密钥
        /// </summary>
        /// <param name="PrivateKey">私钥</param>
        /// <param name="PublicKey">公钥</param>
        /// <param name="KeySize">密钥长度512,1024,2048，4096</param>
        public static void Generate(out string PrivateKey, out string PublicKey, int KeySize = 2048)
        {
            //初始化加密对象，并且设置密钥的长度
            RSACryptoServiceProvider serviceProvider = new RSACryptoServiceProvider(KeySize);
            //false 表示仅包含公钥。
            PublicKey = serviceProvider.ToXmlString(false);
            //true 表示同时包含 RSA 公钥和私钥
            PrivateKey = serviceProvider.ToXmlString(true);
        }
  　　　　/// <summary>
        /// 加密
        /// </summary>
        /// <param name="PublicKey">公钥</param>
        /// <param name="EncryptString">待加密字符串</param>
        /// <returns></returns>
        public static string RSAEncrypt(string PublicKey, string EncryptString)
        {
            byte[] inputByArray;
            byte[] outPutByArray;
            string result;
            RSACryptoServiceProvider serviceProvider = new RSACryptoServiceProvider();
            serviceProvider.FromXmlString(PublicKey);
            inputByArray = Encoding.UTF8.GetBytes(EncryptString);
            outPutByArray = serviceProvider.Encrypt(inputByArray, false);
            result = Convert.ToBase64String(outPutByArray);
            return result;
        }
　　　　　/// <summary>
        /// 解密
        /// </summary>
        /// <param name="PrivateKey">私钥</param>
        /// <param name="DecryptString">待加密字符串</param>
        /// <returns></returns>
        public static string RSADecrypt(string PrivateKey, string DecryptString)
        {
            byte[] inputByArray;
            byte[] outPutByArray;
            string result;
            RSACryptoServiceProvider serviceProvider = new RSACryptoServiceProvider();
            serviceProvider.FromXmlString(PrivateKey);
            inputByArray = Convert.FromBase64String(DecryptString);
            outPutByArray = serviceProvider.Decrypt(inputByArray, false);
            result = Encoding.UTF8.GetString(outPutByArray);
            return result;
        }

    }

        static void Main(string[] args)
        {
            string PrivateKey;
            string PublicKey;
            RSA.Generate(out PrivateKey, out PublicKey);
            Console.WriteLine("私钥的值：{0}，公钥的值：{1}", PrivateKey, PublicKey);
            var encryptResult = RSA.RSAEncrypt(PublicKey, "123456");
            var decryptResult = RSA.RSADecrypt(PrivateKey, encryptResult);
            Console.WriteLine("加密后的值：{0}，解密后的值：{1}", encryptResult, decryptResult);
        }