?using System;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;
using System.IO;

namespace ZYBEncrypt
{
    /// <summary>
    /// 非對稱RSA
    /// </summary>
    public class RSA_
    {
        private RSACryptoServiceProvider rsa;
        public RSA_()
        {
            rsa = new RSACryptoServiceProvider();
        }
        /// <summary>
        /// 得到公鑰
        /// </summary>
        /// <returns></returns>
        public string GetPublicKey()
        {
            return rsa.ToXmlString(false);
        }
        /// <summary>
        /// 得到私鑰
        /// </summary>
        /// <returns></returns>
        public string GetPrivateKey()
        {
            return rsa.ToXmlString(true);
           
        }
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="Source">待加密字符串</param>
        /// <param name="PublicKey">公鑰</param>
        /// <returns></returns>
        public string Encrypt(string Source, string PublicKey)
        {
            rsa.FromXmlString(PublicKey);
            byte[] done= rsa.Encrypt(Convert.FromBase64String(Source), false);
            return Convert.ToBase64String(done);
        }
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="Source">待加密字符數(shù)組</param>
        /// <param name="PublicKey">公鑰</param>
        /// <returns></returns>
        public byte[] Encrypt(byte[] Source, string PublicKey)
        {
            rsa.FromXmlString(PublicKey);
            return rsa.Encrypt(Source, false);
        }
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="inFileName">待加密文件路徑</param>
        /// <param name="outFileName">加密后文件路徑</param>
        /// <param name="PublicKey">公鑰</param>
        public void Encrypt(string inFileName, string outFileName, string PublicKey)
        {
            rsa.FromXmlString(PublicKey);
            FileStream fin = new FileStream(inFileName, FileMode.Open, FileAccess.Read);
            FileStream fout = new FileStream(outFileName, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength(0);

            byte[] bin = new byte[1000];
            long rdlen = 0;
            long totlen = fin.Length;
            int len;

            while (rdlen < totlen)
            {
                len = fin.Read(bin, 0, 1000);
                byte[] bout=rsa.Encrypt(bin,false);
                fout.Write(bout, 0, bout.Length);
                rdlen = rdlen + len;
            }
          
            fout.Close();
            fin.Close();

        }
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="Source">待解密字符串</param>
        /// <param name="PrivateKey">私鑰</param>
        /// <returns></returns>
        public string Decrypt(string Source, string PrivateKey)
        {
            rsa.FromXmlString(PrivateKey);
            byte[] done = rsa.Decrypt(Convert.FromBase64String(Source), false);
            return Convert.ToBase64String(done);
        }
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="Source">待解密字符數(shù)組</param>
        /// <param name="PrivateKey">私鑰</param>
        /// <returns></returns>
        public byte[] Decrypt(byte[] Source, string PrivateKey)
        {
            rsa.FromXmlString(PrivateKey);
            return rsa.Decrypt(Source, false);
        }
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="inFileName">待解密文件路徑</param>
        /// <param name="outFileName">解密后文件路徑</param>
        /// <param name="PrivateKey">私鑰</param>
        public void Decrypt(string inFileName, string outFileName, string PrivateKey)
        {
            rsa.FromXmlString(PrivateKey);
            FileStream fin = new FileStream(inFileName, FileMode.Open, FileAccess.Read);
            FileStream fout = new FileStream(outFileName, FileMode.OpenOrCreate, FileAccess.Write);
            fout.SetLength(0);

            byte[] bin = new byte[1000];
            long rdlen = 0;
            long totlen = fin.Length;
            int len;

            while (rdlen < totlen)
            {
                len = fin.Read(bin, 0, 1000);
                byte[] bout = rsa.Decrypt(bin, false);
                fout.Write(bout, 0, bout.Length);
                rdlen = rdlen + len;
            }
            
            fout.Close();
            fin.Close();

        }
    }
}