dquakeplus/source/crypter.c

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2022-02-08 21:49:56 +00:00
/*
DATA Decrypt
*/
#include <stdlib.h>
#include <ctype.h>
char rotate(char c, int key)
{
int l = 'Z' - 'A';
c += key % l;
if(c < 'A')
c += l;
if(c > 'Z')
c -= l;
return c;
}
char encrypt(char c, int key)
{
if(c >= 'a' && c <= 'z')
c = toupper(c);
if(c >= 'A' && c <= 'Z')
c = rotate(c, key);
return c;
}
char decrypt(char c, int key)
{
if(c < 'A' || c > 'Z')
return c;
else
return rotate(c, key);
}
char *strencrypt(char *s, int key, int len)
{
int i;
char *result = malloc(len);
for(i = 0; i < len; i++)
{
result[i] = encrypt(s[i], key);
}
return result;
}
char *strdecrypt(char *s, int key, int len)
{
int i;
char *result = malloc(len);
for(i = 0; i < len; i++)
{
result[i] = decrypt(s[i], -key);
}
return result;
}