Vernam加密法 Playfair密码加密

Vernam加密法：

#include <stdio.h>
#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <ctype.h>
#include <algorithm>
#include <vector>
#include <string.h>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <sstream>
#include <time.h>

using namespace std;

char clear_text[10000];
string ans;
char key[10000];

int main()
{
    memset(key, 0, sizeof(key));
    ans.clear();

    printf("please enter the clear_text :");
    scanf("%s", clear_text);
    int len = strlen(clear_text);
    printf("please enter key :");
    scanf("%s", &key);
    for (int i = 0;i < len;i++)
    {
        int tmp = (clear_text[i] - 'a' + key[i] - 'a') % 26;
        ans += (char)(tmp + 'a');
    }
    cout << ans << endl;
    return 0;
}

Playfair密码加密：

#include <stdio.h>
#include <iostream>
#include <math.h>
#include <stdlib.h>
#include <ctype.h>
#include <algorithm>
#include <vector>
#include <string.h>
#include <string>
#include <queue>
#include <stack>
#include <set>
#include <sstream>
#include <time.h>

using namespace std;

char key[100];
int mat[30][30];
string text, ans;
bool vis[30];

void init()
{
    memset(vis, false, sizeof(vis));
    memset(mat, 0, sizeof(mat));
    ans.clear();
    text.clear();
}

struct Loca
{
    int x, y;
}loc[100];

int main()
{
    init();
    printf("please entry the key :");
    scanf("%s", key);
    int len = strlen(key);
    int tot = 0;
    for (int i = 0;i < len;i++)
    {
        if (!vis[key[i] - 'a'])
        {
            int x = tot / 5;
            int y = tot % 5;
            loc[key[i] - 'a'].x = x;
            loc[key[i] - 'a'].y = y;
            mat[x][y] = key[i] - 'a';
            vis[key[i] - 'a'] = true;
            if (key[i] == 'i' || key[i] == 'j')
            {
                vis['i' - 'a'] = vis['j' - 'a'] = true;
                loc['i' - 'a'].x = x;
                loc['i' - 'a'].y = y;
                loc['j' - 'a'].x = x;
                loc['j' - 'a'].y = y;
            }
            tot++;
        }
    }

    int pos = 0;
    while (1)
    {
        if (!vis[pos])
        {
            int x = tot / 5;
            int y = tot % 5;
            loc[pos].x = x;
            loc[pos].y = y;
            mat[x][y] = pos;
            vis[pos] = true;
            if (pos == 'i' - 'a' || pos == 'j' - 'a')
            {
                vis['i' - 'a'] = vis['j' - 'a'] = true;
                loc['i' - 'a'].x = x;
                loc['i' - 'a'].y = y;
                loc['j' - 'a'].x = x;
                loc['j' - 'a'].y = y;
            }
            tot++;
        }
        pos++;
        if (pos == 26) break;
    }

    printf("plaese enter the  clear text :");
    cin >> text;
    if (text.size() % 2) text += 'm';//事先约定奇数+’m‘

    //开始加密
    for (int i = 0;i < text.size();i += 2)
    {
        int u = text[i] - 'a';
        int v = text[i + 1] - 'a';
        int x1 = loc[u].x;
        int y1 = loc[u].y;
        int x2 = loc[v].x;
        int y2 = loc[v].y;
        if (x1 == x2 && y1 == y2)//事先约定相同算作为"fq"
            ans += "fq";
        else if (x1 == x2)
        {
            int tmp = (y1 + 1) % 5;
            while (tmp == y1 || tmp == y2)
                tmp = (tmp + 1) % 5;
            ans += mat[x1][tmp] + 'a';

            int tmp2 = (y2 + 1) / 5;
            while (tmp2 == y1 || tmp2 == y2 || tmp2 == tmp)
                tmp2 = (tmp2 + 1) % 5;
            ans += mat[x2][tmp2] + 'a';
        }
        else if (y1 == y2)
        {
            int tmp = (x1 + 1) % 5;
            while (tmp == x1 || tmp == x2)
                tmp = (tmp + 1) % 5;
            ans += mat[tmp][y1] + 'a';

            int tmp2 = (x2 + 1) % 5;
            while (tmp == x1 || tmp == x2 || tmp2 == tmp)
                tmp2 = (tmp2 + 1) % 5;
            ans += mat[tmp2][y2] + 'a';
        }
        else if (x1 != x2 && y1 != y2)
        {
            ans += mat[x1][y2] + 'a';
            ans += mat[x2][y1] + 'a';
        }
    }
    cout << ans << endl;
    return 0;
}
/*
hello
university
*/