libsodium/test/default/secretbox8.c

#include <stdio.h>
#include <stdlib.h>

#define TEST_NAME "secretbox8"
#include "cmptest.h"

unsigned char k[crypto_secretbox_KEYBYTES];
unsigned char n[crypto_secretbox_NONCEBYTES];
unsigned char m[10000];
unsigned char c[10000];
unsigned char m2[10000];

int main(void)
{
  int mlen;
  int i;
  int caught;

  for (mlen = 0;mlen < 1000 && mlen + crypto_secretbox_ZEROBYTES < sizeof m;++mlen) {
    randombytes(k,crypto_secretbox_KEYBYTES);
    randombytes(n,crypto_secretbox_NONCEBYTES);
    randombytes(m + crypto_secretbox_ZEROBYTES,mlen);
    crypto_secretbox(c,m,mlen + crypto_secretbox_ZEROBYTES,n,k);
    caught = 0;
    while (caught < 10) {
      c[random() % (mlen + crypto_secretbox_ZEROBYTES)] = random();
      if (crypto_secretbox_open(m2,c,mlen + crypto_secretbox_ZEROBYTES,n,k) == 0) {
        for (i = 0;i < mlen + crypto_secretbox_ZEROBYTES;++i)
          if (m2[i] != m[i]) {
	    printf("forgery\n");
	    return 100;
	  }
      } else {
        ++caught;
      }
    }
  }
  return 0;
}