c - some problem with byte xor -

i have make binary xor on 2 byte buffers. 1 encoding key, other encoded value.

at moment code looks this:

byte key[]={"somekey"} byte value[]={"somevalue"};  for(i= 0; < valllength; i++)     {         valbuf[i] = value[i] ^ key[i % keylength];     } 

this not work me. doing wrong?

alright, terrible, felt writing easy code change.

#include <stdio.h>  char key[] = "this fancy key."; char text[] = "encrypt extremely long plaintext."; #define key_len (sizeof(key)) #define txt_len (sizeof(text))  void crypt(char *key, char *plaintext, char *ciphertext, int keylen, int ptlen) {         int idx;     (idx = 0; idx < ptlen; idx++)     {         ciphertext[idx] = plaintext[idx] ^ key[idx % keylen];     } }  int main() {     printf("plaintext before:\n\t%s\n", text);     crypt(key, text, text, key_len, txt_len);     printf("plaintext after:\n\t%s\n", text);     crypt(key, text, text, key_len, txt_len);     printf("plaintext after after:\n\t%s\n", text);     return 0; } 

this question's destined closure anyway, can't hurt post here.