// Copyright 2026 Google LLC

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//     http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#include <assert.h>

#include <stdlib.h>

#include <sodium.h>

#include "fake_random.h"

extern "C" int LLVMFuzzerTestOneInput(const unsigned char *data, size_t size) {

  int initialized = sodium_init();

  assert(initialized >= 0);

  if (size < crypto_box_SEEDBYTES + crypto_box_NONCEBYTES) {

    return 0;

  }

  setup_fake_random(data, size);

  unsigned char pk1[crypto_box_PUBLICKEYBYTES];

  unsigned char sk1[crypto_box_SECRETKEYBYTES];

  unsigned char pk2[crypto_box_PUBLICKEYBYTES];

  unsigned char sk2[crypto_box_SECRETKEYBYTES];

  const unsigned char *seed1 = data;

  const unsigned char *nonce = data + crypto_box_SEEDBYTES;

  const unsigned char *msg = nonce + crypto_box_NONCEBYTES;

  size_t msg_len = size - (crypto_box_SEEDBYTES + crypto_box_NONCEBYTES);

  // Generate keypairs. Using seed for the first one to be more deterministic from input.

  crypto_box_seed_keypair(pk1, sk1, seed1);

  // Second keypair can be generated normally, but randombytes is hooked so it's also deterministic.

  crypto_box_keypair(pk2, sk2);

  unsigned char *ciphertext = (unsigned char *) malloc(msg_len + crypto_box_MACBYTES);

  int err = crypto_box_easy(ciphertext, msg, msg_len, nonce, pk2, sk1);

  assert(err == 0);

  unsigned char *decrypted = (unsigned char *) malloc(msg_len);

  err = crypto_box_open_easy(decrypted, ciphertext, msg_len + crypto_box_MACBYTES, nonce, pk1, sk2);

  assert(err == 0);

  assert(memcmp(decrypted, msg, msg_len) == 0);

  free(ciphertext);

  free(decrypted);

  return 0;

}