利用RSACryptoServiceProvider进行RSA加密解密

前言：

本文只介绍How to use，对于加密算法的研究不予讨论。

关于私钥的存储，微软给的建议是使用windows自带的秘钥容器，相见文档。

为了直观看到私钥和公钥，本文直接将其存入XML文件中。现实情况则要复杂的多，还牵涉到数字签名、数字证书等。

关于公钥、私钥、数字签名、数字证书的概念，相见阮一峰大神的博客，传送门在这里。

 

正文：

由于RSA不适合加密大量数据，所以可以采用DES和RSA混合加密的方法，即先用DES加密数据，再用RSA加密DES的秘钥。

 

RSAHelper 类

public class RSAHelper
    {
        /// <summary>
        /// 读取二进制文件
        /// </summary>
        /// <param name="path"></param>
        /// <returns></returns>
        public static byte[] GetByte(string path)
        {
            FileInfo fi = new FileInfo(path);
            List<byte> buff = new List<byte>();
            using (FileStream fs = fi.Open(FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                BinaryReader br = new BinaryReader(fs);
                try
                {
                    while (true)
                    {
                        byte i = br.ReadByte();
                        buff.Add(i);
                    }
                }
                catch (Exception)
                {
                    br.Close();
                }
            }
            return buff.ToArray();
        }

        /// <summary>
        /// 读取文本文件
        /// </summary>
        /// <param name="path"></param>
        /// <returns></returns>
        public static string GetText(string path)
        {
            FileInfo fi = new FileInfo(path);
            string content;
            using (FileStream fs = fi.Open(FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                StreamReader sr = new StreamReader(fs);
                content = sr.ReadToEnd();
                sr.Close();
            }
            return content;
        }

        /// <summary>
        /// 写入二进制文件
        /// </summary>
        /// <param name="content"></param>
        /// <param name="path"></param>
        public static void WriteByte(byte[] content, string path)
        {
            FileInfo fi = new FileInfo(path);
            using (FileStream fs = fi.Open(FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                BinaryWriter br = new BinaryWriter(fs);
                br.Write(content);
                br.Flush();
                br.Close();
            }
        }

        /// <summary>
        /// 写入文本文件
        /// </summary>
        /// <param name="content"></param>
        /// <param name="path"></param>
        public static void WriteText(string content, string path)
        {
            FileInfo fi = new FileInfo(path);
            using (FileStream fs = fi.Open(FileMode.OpenOrCreate, FileAccess.ReadWrite))
            {
                StreamWriter sw = new StreamWriter(fs);
                sw.Write(content);
                sw.Flush();
                sw.Close();
            }
        }

        /// <summary>
        /// RSA加密/解密
        /// </summary>
        /// <param name="data">加密/解密数据</param>
        /// <param name="key">公钥/私钥</param>
        /// <param name="isEncrypt">ture加密，false解密</param>
        /// <returns></returns>
        public static byte[] EncryptOrDecrypt(byte[] data, string key, bool isEncrypt)
        {
            RSACryptoServiceProvider rsaP = new RSACryptoServiceProvider();
            rsaP.FromXmlString(key);
            if (isEncrypt)// 加密
            {
                byte[] buff = rsaP.Encrypt(data, true);
                return buff;
            }
            else // 解密
            {
                byte[] buff = rsaP.Decrypt(data, true);
                return buff;
            }

        } 
    }

RSAHelper类