/*
	Validate ed25519 implementation against the official test vectors from 
	http://ed25519.cr.yp.to/software.html
*/

#include <stdio.h>
#include <string.h>
#include "ed25519.h"

#include "test-ticks.h"

static void
edassert(int check, int round, const char *failreason) {
	if (check)
		return;
	printf("round %d, %s\n", round, failreason);
	exit(1);
}

static void
edassert_die(const unsigned char *a, const unsigned char *b, size_t len, int round, const char *failreason) {
	size_t i;
	if (round > 0)
		printf("round %d, %s\n", round, failreason);
	else
		printf("%s\n", failreason);
	printf("want: "); for (i = 0; i < len; i++) printf("%02x,", a[i]); printf("\n");
	printf("got : "); for (i = 0; i < len; i++) printf("%02x,", b[i]); printf("\n");
	printf("diff: "); for (i = 0; i < len; i++) if (a[i] ^ b[i]) printf("%02x,", a[i] ^ b[i]); else printf("  ,"); printf("\n\n");
	exit(1);
}

static void
edassert_equal(const unsigned char *a, const unsigned char *b, size_t len, const char *failreason) {
	if (memcmp(a, b, len) == 0)
		return;
	edassert_die(a, b, len, -1, failreason);
}

static void
edassert_equal_round(const unsigned char *a, const unsigned char *b, size_t len, int round, const char *failreason) {
	if (memcmp(a, b, len) == 0)
		return;
	edassert_die(a, b, len, round, failreason);
}


/* test data */
typedef struct test_data_t {
	unsigned char sk[32], pk[32], sig[64];
	const char *m;
} test_data;


test_data dataset[] = {
#include "regression.h"
};

/* result of the curve25519 scalarmult ((|255| * basepoint) * basepoint)... 1024 times */
const curved25519_key curved25519_expected = {
	0xac,0xce,0x24,0xb1,0xd4,0xa2,0x36,0x21,
	0x15,0xe2,0x3e,0x84,0x3c,0x23,0x2b,0x5f,
	0x95,0x6c,0xc0,0x7b,0x95,0x82,0xd7,0x93,
	0xd5,0x19,0xb6,0xf1,0xfb,0x96,0xd6,0x04
};


/* from ed25519-donna-batchverify.h */
extern unsigned char batch_point_buffer[3][32];

/* y coordinate of the final point from 'amd64-51-30k' with the same random generator */
static const unsigned char batch_verify_y[32] = {
	0x51,0xe7,0x68,0xe0,0xf7,0xa1,0x88,0x45,
	0xde,0xa1,0xcb,0xd9,0x37,0xd4,0x78,0x53,
	0x1b,0x95,0xdb,0xbe,0x66,0x59,0x29,0x3b,
	0x94,0x51,0x2f,0xbc,0x0d,0x66,0xba,0x3f
};

/*
static const unsigned char batch_verify_y[32] = {
	0x5c,0x63,0x96,0x26,0xca,0xfe,0xfd,0xc4,
	0x2d,0x11,0xa8,0xe4,0xc4,0x46,0x42,0x97,
	0x97,0x92,0xbe,0xe0,0x3c,0xef,0x96,0x01,
	0x50,0xa1,0xcc,0x8f,0x50,0x85,0x76,0x7d
};

Introducing the 128 bit r scalars to the heap _before_ the largest scalar
fits in to 128 bits alters the heap shape and produces a different,
yet still neutral/valid y/z value.

This was the value of introducing the r scalars when the largest scalar fit
in to 135-256 bits. You can produce it with amd64-64-24k / amd64-51-32k
with the random sequence used in the first pass by changing

    unsigned long long hlen=((npoints+1)/2)|1;

to

    unsigned long long hlen=npoints;

in ge25519_multi_scalarmult.c

ed25519-donna-batchverify.h has been modified to match the 
default amd64-64-24k / amd64-51-32k behaviour
*/



/* batch test */
#define test_batch_count 64
#define test_batch_rounds 96

typedef enum batch_test_t {
	batch_no_errors = 0,
	batch_wrong_message = 1,
	batch_wrong_pk = 2,
	batch_wrong_sig = 3
} batch_test;

static int
test_batch_instance(batch_test type, uint64_t *ticks) {
	ed25519_secret_key sks[test_batch_count];
	ed25519_public_key pks[test_batch_count];
	ed25519_signature sigs[test_batch_count];
	unsigned char messages[test_batch_count][128];
	size_t message_lengths[test_batch_count];
	const unsigned char *message_pointers[test_batch_count];
	const unsigned char *pk_pointers[test_batch_count];
	const unsigned char *sig_pointers[test_batch_count];
	int valid[test_batch_count], ret, validret;
	size_t i;
	uint64_t t;

	/* generate keys */
	for (i = 0; i < test_batch_count; i++) {
		ed25519_randombytes_unsafe(sks[i], sizeof(sks[i]));
		ed25519_publickey(sks[i], pks[i]);
		pk_pointers[i] = pks[i];
	}

	/* generate messages */
	ed25519_randombytes_unsafe(messages, sizeof(messages));
	for (i = 0; i < test_batch_count; i++) {
		message_pointers[i] = messages[i];
		message_lengths[i] = (i & 127) + 1;
	}

	/* sign messages */
	for (i = 0; i < test_batch_count; i++) {
		ed25519_sign(message_pointers[i], message_lengths[i], sks[i], pks[i], sigs[i]);
		sig_pointers[i] = sigs[i];
	}

	validret = 0;
	if (type == batch_wrong_message) {
		message_pointers[0] = message_pointers[1];
		validret = 1|2;
	} else if (type == batch_wrong_pk) {
		pk_pointers[0] = pk_pointers[1];
		validret = 1|2;
	} else if (type == batch_wrong_sig) {
		sig_pointers[0] = sig_pointers[1];
		validret = 1|2;
	}

	/* batch verify */
	t = get_ticks();
	ret = ed25519_sign_open_batch(message_pointers, message_lengths, pk_pointers, sig_pointers, test_batch_count, valid);
	*ticks = get_ticks() - t;
	edassert_equal((unsigned char *)&validret, (unsigned char *)&ret, sizeof(int), "batch return code");
	for (i = 0; i < test_batch_count; i++) {
		validret = ((type == batch_no_errors) || (i != 0)) ? 1 : 0;
		edassert_equal((unsigned char *)&validret, (unsigned char *)&valid[i], sizeof(int), "individual batch return code");
	}
	return ret;
}

static void
test_batch(void) {
	uint64_t dummy_ticks, ticks[test_batch_rounds], best = maxticks, sum;
	size_t i, count;

	/* check the first pass for the expected result */
	test_batch_instance(batch_no_errors, &dummy_ticks);
	edassert_equal(batch_verify_y, batch_point_buffer[1], 32, "failed to generate expected result");

	/* make sure ge25519_multi_scalarmult_vartime throws an error on the entire batch with wrong data */
	for (i = 0; i < 4; i++) {
		test_batch_instance(batch_wrong_message, &dummy_ticks);
		test_batch_instance(batch_wrong_pk, &dummy_ticks);
		test_batch_instance(batch_wrong_sig, &dummy_ticks);
	}

	/* speed test */
	for (i = 0; i < test_batch_rounds; i++) {
		test_batch_instance(batch_no_errors, &ticks[i]);
		if (ticks[i] < best)
			best = ticks[i];
	}

	/* take anything within 1% of the best time */
	for (i = 0, sum = 0, count = 0; i < test_batch_rounds; i++) {
		if (ticks[i] < (best * 1.01)) {
			sum += ticks[i];
			count++;
		}
	}
	printf("%.0f ticks/verification\n", (double)sum / (count * test_batch_count));
}

static void
test_main(void) {
	int i, res;
	ed25519_public_key pk;
	ed25519_signature sig;
	unsigned char forge[1024] = {'x'};
	curved25519_key csk[2] = {{255}};
	uint64_t ticks, pkticks = maxticks, signticks = maxticks, openticks = maxticks, curvedticks = maxticks;

	for (i = 0; i < 1024; i++) {
		ed25519_publickey(dataset[i].sk, pk);
		edassert_equal_round(dataset[i].pk, pk, sizeof(pk), i, "public key didn't match");
		ed25519_sign((unsigned char *)dataset[i].m, i, dataset[i].sk, pk, sig);
		edassert_equal_round(dataset[i].sig, sig, sizeof(sig), i, "signature didn't match");
		edassert(!ed25519_sign_open((unsigned char *)dataset[i].m, i, pk, sig), i, "failed to open message");

		memcpy(forge, dataset[i].m, i);
		if (i)
			forge[i - 1] += 1;

		edassert(ed25519_sign_open(forge, (i) ? i : 1, pk, sig), i, "opened forged message");
	}

	for (i = 0; i < 1024; i++)
		curved25519_scalarmult_basepoint(csk[(i & 1) ^ 1], csk[i & 1]);
	edassert_equal(curved25519_expected, csk[0], sizeof(curved25519_key), "curve25519 failed to generate correct value");

	for (i = 0; i < 2048; i++) {
		timeit(ed25519_publickey(dataset[0].sk, pk), pkticks)
		edassert_equal_round(dataset[0].pk, pk, sizeof(pk), i, "public key didn't match");
		timeit(ed25519_sign((unsigned char *)dataset[0].m, 0, dataset[0].sk, pk, sig), signticks)
		edassert_equal_round(dataset[0].sig, sig, sizeof(sig), i, "signature didn't match");
		timeit(res = ed25519_sign_open((unsigned char *)dataset[0].m, 0, pk, sig), openticks)
		edassert(!res, 0, "failed to open message");
		timeit(curved25519_scalarmult_basepoint(csk[1], csk[0]), curvedticks);
	}

	printf("%.0f ticks/public key generation\n", (double)pkticks);
	printf("%.0f ticks/signature\n", (double)signticks);
	printf("%.0f ticks/signature verification\n", (double)openticks);
	printf("%.0f ticks/curve25519 basepoint scalarmult\n", (double)curvedticks);
}

int
main(void) {
	test_main();
	test_batch();
	return 0;
}