#include "sodium/randombytes.h" unsigned char x[65536]; unsigned long long freq[256]; int main(void) { unsigned long long i; randombytes(x,sizeof x); for (i = 0;i < 256;++i) freq[i] = 0; for (i = 0;i < sizeof x;++i) ++freq[255 & (int) x[i]]; for (i = 0;i < 256;++i) if (!freq[i]) return 111; return 0; }