xor.c

#include <stddef.h>

#include "xor.h"

void *memxor(void *s, size_t ssize, void *k, size_t ksize)
{
    unsigned char *sp = s;
    unsigned char *kp = k;

    for (size_t i = 0; i < ssize; ++i) {
        sp[i] ^= kp[i % ksize];
    }

    return s;
}