古典密码学(替换、置换加密)C程序

替换：

#include

int encrypt( )

{

char STR[27]= {'X','N','Y','A','H','P','O','G','Z','Q','W','B','T','S','F','L','R','C','V','M','U','E','K','J','D','I'};

char str[27]={'d','l','r','y','v','o','h','e','z','x','w','p','t','b','g','f','j','q','n','m','u','s','k','a','c','i'};

int x,i=0;

char code[80],string[80];

printf("请输入你的明文(80字符内的小写字符串)：");

scanf("%s",string);

printf("The code is:");

for(i=0;string[i];i++)

{

x=string[i]-97;

code[i]=STR[x];

printf("%c",STR[x]);

}

printf("\n");

return 0;

}

int decrypt( )

{

char STR[27]= {'X','N','Y','A','H','P','O','G','Z','Q','W','B','T','S','F','L','R','C','V','M','U','E','K','J','D','I'};

char str[27]={'d','l','r','y','v','o','h','e','z','x','w','p','t','b','g','f','j','q','n','m','u','s','k','a','c','i'};

int x,i=0;

char decode[80],STRING[80];

printf("请输入你的密文(80字符内的大写字符串)：");

scanf("%s",STRING);

printf("The decode is:");

for(i=0;STRING[i];i++)

{

x=STRING[i]-65;

decode[i]=str[x];

printf("%c",str[x]);

}

printf("\n");

return 0;

}

int main()

{

char STR[27]= {'X','N','Y','A','H','P','O','G','Z','Q','W','B','T','S','F','L','R','C','V','M','U','E','K','J','D','I'};

char str[27]={'d','l','r','y','v','o','h','e','z','x','w','p','t','b','g','f','j','q','n','m','u','s','k','a','c','i'};

int t,x,y=0,i=0;

char code[80],string[80];

char decode[80],STRING[80];

printf("加密请输入1，解密请输入0:");

scanf("%d",&t);

printf("\n");

if(t==1)

{

encrypt();

for(i=0;code[i];i++)

{

x=code[i]-65;

decode[i]=str[x];

if(decode[i]==string[i])

y++;

else y=y;

}

if(y==i-1)

printf("CRYPT_OK!\n");

else printf("CRYPT_ERROR!\n");

}

else if(t==0)

{

decrypt();

for(i=0;decode[i];i++)

{

x=decode[i]-65;

code[i]=STR[x];

if(code[i]==STRING[i])

y++;

else y=y;

}

if(y==i-125)

printf("CRYPT_OK!\n");

else printf("CRYPT_ERROR!\n");

}

else

printf("ERROR!\n");

return 0;

}

置换：

#include

#include

#include

char *encrypt(char *str,int n)

{

int i,j,k,l,d;

char *c,*s1,*c1;

l=strlen(str);

if((d=l%n)!=0) l=l+n-d;

if((s1=(char *)malloc(l*sizeof(char)+1))==NULL) {

printf("Memory error!\n");

exit(l);

}

if((c=(char *)malloc(l*sizeof(char)+1))==NULL)

{

printf("Memory error!\n");

exit(l);

}

c1=c;

strcpy(s1,str);

for(i=strlen(str);i

s1[i]=32;

s1[l]='\0';

for(k=0;k

{

for(j=0;j

{

*c1=s1[k+j*n];

c1++;

}

}

*c1='\0';

free(s1);

return c;

}