四種加密解密算法的源代碼：移位密碼、仿射密碼、維吉尼亞密碼以及置換密碼

四種加密解密算法的源代碼：移位密碼、仿射密碼、維吉尼亞密碼以及置換密碼

#include <stdio.h>

#include <conio.h>

#include <string.h>

#include <malloc.h>

void Shift()

{

char c[100];

int length, i=0, key=0;

clrscr();

printf("********Shift Cipher********/nPlease input primal sentence: ");

gets(c);

length = strlen(c);

printf("Input the key(0~26): ");

scanf("%d", &key);

getchar();

if(key<0)

{

printf("The value of key is error!/nPress any key to return...");

getch();

return;

}

for(i=0; i<length; i++)

{

if(c[i]>96&&c[i]<123)

c[i] = (c[i]+key-97)%26+65;

else if(c[i]>64&&c[i]<91)

c[i] = (c[i]+key-65)%26+65;

}

printf("Result is: %s/n", c);

for(i=0; i<length; i++)

{

if(c[i]>64&&c[i]<91)

c[i] = (c[i]-key-65+26)%26+97;

}

printf("/nAfter translated the sentence,we can see the primal sentence as follow:/n%s/n", c);

printf("Press any key to return...");

getch();

}

int gcd(int a, int b)

{

int k = 0;

do

{

k = a%b;

a = b;

b = k;

}while(k!=0);

return a;

}

int Ni(int a, int b)

{

int i = 0;

while(a*(++i)%b!=1);

return i;

}

void Affine()

{

char c[100];

int length, i=0, ka=0, kb=0, tmp;

clrscr();

printf("********Affine Cipher********/nPlease input primal sentence: ");

gets(c);

length = strlen(c);

printf("Input the key(2 numbers): ");

scanf("%d%d", &ka, &kb);

getchar();

if(gcd(ka,26)!=1)

{

printf("The value of the key is error!/nPress any key to return...");

return;

}

for(i=0; i<length; i++)

{

if(c[i]>96&&c[i]<123)

c[i] = (ka*(c[i]-97)+kb)%26+65;

else if(c[i]>64&&c[i]<91)

c[i] = (ka*(c[i]-65)+kb)%26+65;

}

printf("Result is: %s/n", c);

for(i=0; i<length; i++)

{

if(c[i]>64&&c[i]<91)

{

tmp = Ni(ka,26)*((c[i]-65)-kb);

if(tmp<0)

c[i] = tmp%26+26+97;

else

c[i] = tmp%26+97;

}

}

printf("/nAfter translated the sentence,we can see the primal sentence as follow:/n%s/n", c);

printf("Press any key to return...");

getch();

}

void Vigenere()

{

char c[100], key[100];

int lenc, lenk, i=0, j=0, tmp;

clrscr();

printf("********Vigenere Cipher********/nPlease input primal sentence: ");

gets(c);

lenc = strlen(c);

strcpy(c, strupr(c));

printf("Input the key: ");

gets(key);

lenk = strlen(key);

strcpy(key, strupr(key));

for(; i<lenc; i++)

{

j = j%lenk;

if(c[i]>64&&c[i]<91)

{

c[i] = (c[i]-65+key[j]-65)%26+65;

j++;

}

}

printf("Result is: %s/n", c);

for(i=0, j=0; i<lenc; i++)

{

j = j%lenk;

if(c[i]>64&&c[i]<91)

{

tmp = c[i]-65-(key[j]-65);

if(tmp>=0)

c[i] = tmp%26+97;

else

c[i] = (tmp+26)%26+97;

j++;

}

}

printf("/nAfter translated the sentence,we can see the primal sentence as follow:/n%s/n", c);

printf("Press any key to return...");

getch();

}

void Permutation()

{

char c[100], *q;

int *key, len, m, i, j=0;

clrscr();

printf("********Permutation Cipher********/nPlease input primal sentence: ");

gets(c);

strcpy(c, strupr(c));

len = strlen(c);

for(i=0; i<len; i++)

{

if(c[i]<65||c[i]>90)

{

for(j=i; j<len-1; j++)

c[j] = c[j+1];

len--;

}

}

c[len] = '/0';

printf("Input the length of the key: ");

scanf("%d", &m);

key = (int)malloc(m*sizeof(int));

q = (int)malloc(len*sizeof(int));

printf("Input the key: ");

for(i=0; i<m; i++)

{

scanf("%d", key+i);

key[i]--;

}

getchar();

for(i=0; i<len; i++)

{

j = (i/m)*m;

q[i] = c[*(key+i%m)+j];

}

q[i] = '/0';

printf("Result is: %s/n", q);

for(i=0, j=0; i<len; i++)

{

j = (i/m)*m;

c[*(key+i%m)+j] = q[i]+32;

}

c[len] = '/0';

printf("After translated the sentence,we can see the primal sentence as follow:/n%s/n", c);

printf("Press any key to return...");

free(key);

free(q);

getch();

}

void main()

{

char i = '0';

clrscr();

while(i!='5')

{

clrscr();

printf("********Press 1~5 to choose:********/n");

printf("1. Shift Cipher/n2. Affine Cipher/n3. Vigenere Cipher/n4. Permutation Cipher/n5. Exit/n");

i = getch();

if(i=='1')

Shift();

else if(i=='2')

Affine();

else if(i=='3')

Vigenere();

else if(i=='4')

Permutation();

else if(i=='5')

break;

}

}