Libsodium crypto_generichash demo

main.c

#include <sodium.h>
#include <stdio.h>
#include <unistd.h>

int main() {
  if (sodium_init() < 0) {
      printf("init error\n");
      return 1;
  }
  unsigned char hash[crypto_generichash_BYTES];
  crypto_generichash_state state;
  crypto_generichash_init(&state, NULL, 0, sizeof(hash));

  unsigned char buf[65536];
  while (1) {
    ssize_t n = read(STDIN_FILENO, buf, sizeof(buf));
    if (n < 0) {
      printf("reading error\n");
      return 1;
    }
    if (n == 0) {
      break;
    }
    crypto_generichash_update(&state, buf, n);
  }

  crypto_generichash_final(&state, hash, sizeof hash);

  for (int i = 0; i < crypto_generichash_BYTES; i++) {
    printf("%02x", hash[i]);
  }
  printf("\n");
}