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/* Copyright (c) 2016, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <math.h>
#include <stdio.h>
#include <string.h>
#include <openssl/crypto.h>
#include <openssl/rand.h>
#include "../test/scoped_types.h"
#include "internal.h"
// Set to 10 for quick execution. Tested up to 1,000,000.
static const int kNumTests = 10;
static bool TestKeys(void) {
// Alice generates a public key.
ScopedNEWHOPE_POLY sk(NEWHOPE_POLY_new());
uint8_t offer_msg[NEWHOPE_OFFERMSG_LENGTH];
NEWHOPE_offer(offer_msg, sk.get());
// Bob derives a secret key and creates a response.
uint8_t accept_msg[NEWHOPE_ACCEPTMSG_LENGTH];
uint8_t accept_key[SHA256_DIGEST_LENGTH];
if (!NEWHOPE_accept(accept_key, accept_msg, offer_msg, sizeof(offer_msg))) {
fprintf(stderr, "ERROR accept key exchange failed\n");
return false;
}
// Alice uses Bob's response to get her secret key.
uint8_t offer_key[SHA256_DIGEST_LENGTH];
if (!NEWHOPE_finish(offer_key, sk.get(), accept_msg, sizeof(accept_msg))) {
fprintf(stderr, "ERROR finish key exchange failed\n");
return false;
}
if (memcmp(offer_key, accept_key, SHA256_DIGEST_LENGTH) != 0) {
fprintf(stderr, "ERROR keys did not agree\n");
return false;
}
return true;
}
static bool TestInvalidSK(void) {
// Alice generates a public key.
uint8_t offer_msg[NEWHOPE_OFFERMSG_LENGTH];
ScopedNEWHOPE_POLY sk(NEWHOPE_POLY_new());
NEWHOPE_offer(offer_msg, sk.get());
// Bob derives a secret key and creates a response.
uint8_t accept_key[SHA256_DIGEST_LENGTH];
uint8_t accept_msg[NEWHOPE_ACCEPTMSG_LENGTH];
if (!NEWHOPE_accept(accept_key, accept_msg, offer_msg, sizeof(offer_msg))) {
fprintf(stderr, "ERROR accept key exchange failed\n");
return false;
}
// Corrupt the secret key. It turns out that you need to corrupt a lot of
// bits to ensure that the key exchange always fails!
sk->coeffs[PARAM_N - 1] = 0;
sk->coeffs[PARAM_N - 2] = 0;
sk->coeffs[PARAM_N - 3] = 0;
sk->coeffs[PARAM_N - 4] = 0;
// Alice uses Bob's response to get her secret key.
uint8_t offer_key[SHA256_DIGEST_LENGTH];
if (!NEWHOPE_finish(offer_key, sk.get(), accept_msg, sizeof(accept_msg))) {
fprintf(stderr, "ERROR finish key exchange failed\n");
return false;
}
if (memcmp(offer_key, accept_key, SHA256_DIGEST_LENGTH) == 0) {
fprintf(stderr, "ERROR keys agreed despite corrupt sk\n");
return false;
}
return true;
}
static bool TestInvalidAcceptMsg(void) {
// Alice generates a public key.
ScopedNEWHOPE_POLY sk(NEWHOPE_POLY_new());
uint8_t offer_msg[NEWHOPE_OFFERMSG_LENGTH];
NEWHOPE_offer(offer_msg, sk.get());
// Bob derives a secret key and creates a response.
uint8_t accept_key[SHA256_DIGEST_LENGTH];
uint8_t accept_msg[NEWHOPE_ACCEPTMSG_LENGTH];
if (!NEWHOPE_accept(accept_key, accept_msg, offer_msg, sizeof(offer_msg))) {
fprintf(stderr, "ERROR accept key exchange failed\n");
return false;
}
// Corrupt the (polynomial part of the) accept message. It turns out that
// you need to corrupt a lot of bits to ensure that the key exchange always
// fails!
accept_msg[PARAM_N - 1] = 0;
accept_msg[PARAM_N - 2] = 0;
accept_msg[PARAM_N - 3] = 0;
accept_msg[PARAM_N - 4] = 0;
// Alice uses Bob's response to get her secret key.
uint8_t offer_key[SHA256_DIGEST_LENGTH];
if (!NEWHOPE_finish(offer_key, sk.get(), accept_msg, sizeof(accept_msg))) {
fprintf(stderr, "ERROR finish key exchange failed\n");
return false;
}
if (!memcmp(offer_key, accept_key, SHA256_DIGEST_LENGTH)) {
fprintf(stderr, "ERROR keys agreed despite corrupt accept message\n");
return false;
}
return true;
}
int main(void) {
for (int i = 0; i < kNumTests; i++) {
if (!TestKeys() ||
!TestInvalidSK() ||
!TestInvalidAcceptMsg()) {
return 1;
}
}
printf("PASS\n");
return 0;
}
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