随机练习：C#实现维吉尼亚加密与解密（解密前提为已知密匙）

  1 using System;

  2 using System.Collections.Generic;

  3 using System.ComponentModel;

  4 using System.Data;

  5 using System.Drawing;

  6 using System.Linq;

  7 using System.Text;

  8 using System.Windows.Forms;

  9 

 10 namespace Vigenere

 11 {

 12     public partial class Form1 : Form

 13     {

 14         private string[,] matrix = new string[26, 26];

 15         private ASCIIEncoding ascii = new ASCIIEncoding();

 16 

 17         //key

 18         private string key;

 19         //code

 20         private string code;

 21         //text

 22         private string text;

 23 

 24         public Form1()

 25         {

 26             InitializeComponent();

 27             #region Generate Virginia Martix

 28             for (int i = 0; i < 26; i++)

 29             {

 30                 for (int j = 0; j < 26; j++)

 31                 {

 32                     int number = 65 + i + j;

 33                     if (number > 90)

 34                     {

 35                         number -= 26;

 36                     }

 37                     byte[] bt = new byte[] { (byte)number };

 38                     matrix[i, j] = ascii.GetString(bt);

 39                 }

 40             }

 41             #endregion

 42         }

 43         //加密

 44         private void button1_Click(object sender, EventArgs e)

 45         {

 46             key = this.txtKey.Text.ToString().ToUpper();

 47             code = "";

 48             text = this.txtText.Text.ToString().ToUpper();

 49             List<int> keyNum = new List<int>(); ;

 50 

 51             for (int i = 0; i < key.Length; i++)

 52             {

 53                 string str = key.Substring(i, 1);

 54                 keyNum.Add((int)ascii.GetBytes(str)[0] - 65);

 55             }

 56 

 57             int index = -1;

 58             for (int i = 0; i < this.text.Length; i++)

 59             {

 60                 if (this.text.Substring(i, 1).ToString() == " ")

 61                 {

 62                     code += " ";

 63                     continue;

 64                 }

 65                 index++;

 66                 code += matrix[keyNum[index % key.Length], (int)ascii.GetBytes(this.text.Substring(i, 1))[0] - 65];

 67             }

 68 

 69             this.txtCode.Text = code.ToString();

 70         }

 71         //解密

 72         private void button2_Click(object sender, EventArgs e)

 73         {

 74             key = this.txtKey.Text.ToString().ToUpper();

 75             code = this.txtCode.Text.ToString().ToUpper();

 76             text = "";

 77             List<int> keyNum = new List<int>(); ;

 78 

 79             for (int i = 0; i < key.Length; i++)

 80             {

 81                 string str = key.Substring(i, 1);

 82                 keyNum.Add((int)ascii.GetBytes(str)[0] - 65);

 83             }

 84 

 85             int index = -1;

 86             for (int i = 0; i < this.code.Length; i++)

 87             {

 88                 if (this.code.Substring(i, 1).ToString() == " ")

 89                 {

 90                     text += " ";

 91                     continue;

 92                 }

 93                 index++;

 94 

 95                 for (int j = 0; j < 26; j++)

 96                 {

 97                     if (this.code.Substring(i, 1).ToString() == matrix[keyNum[index % key.Length], j])

 98                     {

 99                         byte[] bt = new byte[] { (byte)(j + 65) };

100                         text += ascii.GetString(bt);

101                     }

102                 }

103             }

104 

105             this.txtText.Text = text.ToString();

106         }

107     }

108 }

对于维吉尼亚方阵及运用维吉尼亚方阵的加密与解密，可参考http://baike.baidu.com/view/270838.htm?fromTaglist

画面结果如下：