算法简述 •
密钥： –
K
＝
k
1
k
2
…
k
d –
第
i
位密钥
k
i
表示采用
k=
k
i
的凯撒替换表 –
密钥重复使用 •
加密算法：
C
i
= E(
p
i
) = (
p
i
+
k
i
) mod 26 •
解密算法：
p
i
= D(C
i
) = (C
i
–
k
i
) mod 26
主要代码如下：
int i,j,m,n,p,q,s,r,temp,res;
s = 0;
char[] str1 = new char[80];
char[ ,] arr = new char[26,26];
Console.WriteLine(“Vigenère Cipher 密码表如下(行代表明文，列代表密钥)：”);
int[] x=new int[80];
int[] y=new int[80];
char[] t = {‘a’,’b’,’c’,’d’,’e’,’f’,’g’,’h’,’i’,’j’,’k’,’l’,’m’,’n’,’o’,’p’,’q’,’r’,’s’,’t’,’u’,’v’,’w’,’x’,’y’,’z’};
char[] t1 = { ‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’, ‘K’, ‘L’, ‘M’, ‘N’, ‘O’, ‘P’, ‘Q’, ‘R’, ‘S’, ‘T’, ‘U’, ‘V’, ‘W’, ‘X’, ‘Y’, ‘Z’ };
for (i = 0; i < 26;i++ )
{
for (j = 0; j < 26;j++ )
{
temp =(i+j) % 26;
arr[i,j] = t1[temp];
Console.Write(arr[i,j] + ” “);
}
Console.WriteLine();
}
Console.WriteLine(“请输入所需要加名的明文：”);
string str = Console.ReadLine();
Console.WriteLine(“请输入加密密钥：”);
string key = Console.ReadLine();
for (m = 0; m < str.Length;m++ )
{
for (n = 0; n < t.Length; n++)
{
if(str[m] == t[n])
{
x[m]=n;
}
}
}
for (p = 0; p < key.Length; p++)
{
for (q = 0; q < t.Length; q++)
{
if (key[p] == t[q])
{
y[p] = q;
}
}
}
for ( r = 0; r < str.Length;r++ )
{
res =( x[s] + y[s]) % 26;
str1[r] = t1[res];
s++;
}
Console.WriteLine(“加密得到的密文为:”);
Console.WriteLine(str1);
Console.ReadKey();
运行结果：
