form1.cs

RC4加解密算法的例程

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace RSA
{
    public partial class Form1 : Form
    {
        Random ran = new Random();

        int RandomKey = 1234567890;

        string Key;

        byte[] S = new byte[256];  //状态向量S
        byte[] T = new byte[256];  //临时向量T
        byte[] K = new byte[16] { 15, 79, 11, 203, 9, 48, 39, 19, 22, 93, 52, 234, 106, 148, 194, 210 };
        int kenlen=16;

        String Plain;
        String Cipher;
        String PlainAfterDecrypt;

        
        public Form1()
        {
            InitializeComponent();
        }

        private void btnInsert_Click(object sender, EventArgs e)
        {
            Stream myStream;
            OpenFileDialog openFileDialog1 = new OpenFileDialog();

            openFileDialog1.InitialDirectory = "c:\\";
            openFileDialog1.Filter = "txt files (*.txt)|*.txt|All files (*.*)|*.*";
            openFileDialog1.FilterIndex = 1;
            openFileDialog1.RestoreDirectory = true;

            if (openFileDialog1.ShowDialog() == DialogResult.OK)
            {
                if ((myStream = openFileDialog1.OpenFile()) != null)
                {
                    string filePath = openFileDialog1.FileName;
                    using (StreamReader reader = new StreamReader(filePath))
                    {
                        while (reader.Peek() > -1)
                        {
                            string lines = reader.ReadToEnd();
                            tMessage.Text = lines;
                        }
                    }

                    myStream.Close();
                }
            }
        }

        private void btnMessageClear_Click(object sender, EventArgs e)
        {
            RandomKey = ran.Next(1,99999);

            Key = Convert.ToString(RandomKey);

            kenlen = Key.Length;

            K = System.Text.ASCIIEncoding.ASCII.GetBytes(Key);

        }

        private void btnGetKey_Click(object sender, EventArgs e)
        {
            tMessage.Text = "";
        }

        private void btnCrypt_Click(object sender, EventArgs e)
        {
            if (tMessage.Text == "")
            {
                MessageBox.Show("请输入需要加密的消息");
                return;
            }

            Plain = tMessage.Text;
            int PlainLength = tMessage.Text.Length;
            int i, j;
            //状态向量S的初始化
            for (i = 0; i < 256; i++)
            {
                S[i] = (byte)i;
                T[i] = K[i % kenlen];
            }

            j = 0;
            byte temp;

            for (i = 0; i < 256; i++)
            {
                j = (j + (int)S[i] + T[i]) % 256;
                temp = S[i];
                S[i] = S[j];
                S[j] = temp;
            }
            //状态向量S的初始化结束

            i = 0;
            j = 0;
            int t;
            char k;
            int n = 0;
            while (PlainLength!=0)
            {
                i = (i + 1) % 256;
                j = (j + S[i]) % 256;
                temp = S[i];
                S[i] = S[j];
                S[j] = temp;
                t= (S[i] + S[j]) % 256;
                k = (char)S[t];
                int Ascii = Plain[n] ^ k;
                char r=(char)Ascii;
                //r = String.Format("{0}", (Plain[n] ^ k));
                Cipher += r;
                n++;
                PlainLength--;
            }

            tCipher.Text = Cipher;



        }

        private void btnCipherClear_Click(object sender, EventArgs e)
        {
            tCipher.Text = "";
        }

        private void btnDeCrypt_Click(object sender, EventArgs e)
        {
            if (tCipher.Text == "")
            {
                MessageBox.Show("请输入需要解密的信息");
                return;
            }

            tResult.Text = "";

//            Cipher = tCipher.Text;
            int CipherLength = Cipher.Length;
            int i, j;
            //状态向量S的初始化
            for (i = 0; i < 256; i++)
            {
                S[i] = (byte)i;
                T[i] = K[i % kenlen];
            }

            j = 0;
            byte temp;

            for (i = 0; i < 256; i++)
            {
                j = (j + (int)S[i] + T[i]) % 256;
                temp = S[i];
                S[i] = S[j];
                S[j] = temp;
            }
            //状态向量S的初始化结束

            i = 0;
            j = 0;
            int t;
            char k;
            int n = 0;
            while ( CipherLength!=0)
            {
                i = (i + 1) % 256;
                j = (j + S[i]) % 256;
                temp = S[i];
                S[i] = S[j];
                S[j] = temp;
                t = (S[i] + S[j]) % 256;
                k = (char)S[t];
                int Ascii = Cipher[n] ^ k;
                char r = (char)Ascii;
                //r = String.Format("{0}", (Plain[n] ^ k));
                PlainAfterDecrypt += r;
                n++;
                CipherLength--;
            }

            tResult.Text = PlainAfterDecrypt;
        }
    }
}