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/* t-cv25519.c - Check the cv25519 crypto
* Copyright (C) 2016 g10 Code GmbH
*
* This file is part of Libgcrypt.
*
* Libgcrypt is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* Libgcrypt is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdarg.h>
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include "stopwatch.h"
#define PGM "t-cv25519"
#include "t-common.h"
#define N_TESTS 18
static void
print_mpi (const char *text, gcry_mpi_t a)
{
gcry_error_t err;
char *buf;
void *bufaddr = &buf;
err = gcry_mpi_aprint (GCRYMPI_FMT_HEX, bufaddr, NULL, a);
if (err)
fprintf (stderr, "%s: [error printing number: %s]\n",
text, gpg_strerror (err));
else
{
fprintf (stderr, "%s: %s\n", text, buf);
gcry_free (buf);
}
}
static void
show_note (const char *format, ...)
{
va_list arg_ptr;
if (!verbose && getenv ("srcdir"))
fputs (" ", stderr); /* To align above "PASS: ". */
else
fprintf (stderr, "%s: ", PGM);
va_start (arg_ptr, format);
vfprintf (stderr, format, arg_ptr);
if (*format && format[strlen(format)-1] != '\n')
putc ('\n', stderr);
va_end (arg_ptr);
}
/* Convert STRING consisting of hex characters into its binary
representation and return it as an allocated buffer. The valid
length of the buffer is returned at R_LENGTH. The string is
delimited by end of string. The function returns NULL on
error. */
static void *
hex2buffer (const char *string, size_t *r_length)
{
const char *s;
unsigned char *buffer;
size_t length;
buffer = xmalloc (strlen(string)/2+1);
length = 0;
for (s=string; *s; s +=2 )
{
if (!hexdigitp (s) || !hexdigitp (s+1))
return NULL; /* Invalid hex digits. */
((unsigned char*)buffer)[length++] = xtoi_2 (s);
}
*r_length = length;
return buffer;
}
static void
reverse_buffer (unsigned char *buffer, unsigned int length)
{
unsigned int tmp, i;
for (i=0; i < length/2; i++)
{
tmp = buffer[i];
buffer[i] = buffer[length-1-i];
buffer[length-1-i] = tmp;
}
}
/*
* Test X25519 functionality through higher layer crypto routines.
*
* Input: K (as hex string), U (as hex string), R (as hex string)
*
* where R is expected result of X25519 (K, U).
*
* It calls gcry_pk_encrypt with Curve25519 private key and let
* it compute X25519.
*/
static void
test_cv_hl (int testno, const char *k_str, const char *u_str,
const char *result_str)
{
gpg_error_t err;
void *buffer = NULL;
size_t buflen;
gcry_sexp_t s_pk = NULL;
gcry_mpi_t mpi_k = NULL;
gcry_sexp_t s_data = NULL;
gcry_sexp_t s_result = NULL;
gcry_sexp_t s_tmp = NULL;
unsigned char *res = NULL;
size_t res_len;
if (verbose > 1)
info ("Running test %d\n", testno);
if (!(buffer = hex2buffer (k_str, &buflen)) || buflen != 32)
{
fail ("error building s-exp for test %d, %s: %s",
testno, "k", "invalid hex string");
goto leave;
}
reverse_buffer (buffer, buflen);
if ((err = gcry_mpi_scan (&mpi_k, GCRYMPI_FMT_USG, buffer, buflen, NULL)))
{
fail ("error converting MPI for test %d: %s", testno, gpg_strerror (err));
goto leave;
}
if ((err = gcry_sexp_build (&s_data, NULL, "%m", mpi_k)))
{
fail ("error building s-exp for test %d, %s: %s",
testno, "data", gpg_strerror (err));
goto leave;
}
xfree (buffer);
if (!(buffer = hex2buffer (u_str, &buflen)) || buflen != 32)
{
fail ("error building s-exp for test %d, %s: %s",
testno, "u", "invalid hex string");
goto leave;
}
/*
* The procedure of decodeUCoordinate will be done internally
* by _gcry_ecc_mont_decodepoint. So, we just put the little-endian
* binary to build S-exp.
*
* We could add the prefix 0x40, but libgcrypt also supports
* format with no prefix. So, it is OK not to put the prefix.
*/
if ((err = gcry_sexp_build (&s_pk, NULL,
"(public-key"
" (ecc"
" (curve \"Curve25519\")"
" (flags djb-tweak)"
" (q%b)))", (int)buflen, buffer)))
{
fail ("error building s-exp for test %d, %s: %s",
testno, "pk", gpg_strerror (err));
goto leave;
}
xfree (buffer);
buffer = NULL;
if ((err = gcry_pk_encrypt (&s_result, s_data, s_pk)))
fail ("gcry_pk_encrypt failed for test %d: %s", testno,
gpg_strerror (err));
s_tmp = gcry_sexp_find_token (s_result, "s", 0);
if (!s_tmp || !(res = gcry_sexp_nth_buffer (s_tmp, 1, &res_len)))
fail ("gcry_pk_encrypt failed for test %d: %s", testno, "missing value");
else
{
char *r, *r0;
int i;
/* To skip the prefix 0x40, for-loop start with i=1 */
r0 = r = xmalloc (2*(res_len)+1);
if (!r0)
{
fail ("memory allocation for test %d", testno);
goto leave;
}
for (i=1; i < res_len; i++, r += 2)
snprintf (r, 3, "%02x", res[i]);
if (strcmp (result_str, r0))
{
fail ("gcry_pk_encrypt failed for test %d: %s",
testno, "wrong value returned");
info (" expected: '%s'", result_str);
info (" got: '%s'", r0);
}
xfree (r0);
}
leave:
xfree (res);
gcry_mpi_release (mpi_k);
gcry_sexp_release (s_tmp);
gcry_sexp_release (s_result);
gcry_sexp_release (s_data);
gcry_sexp_release (s_pk);
xfree (buffer);
}
/*
* Test X25519 functionality through the API for X25519.
*
* Input: K (as hex string), U (as hex string), R (as hex string)
*
* where R is expected result of X25519 (K, U).
*
*/
static void
test_cv_x25519 (int testno, const char *k_str, const char *u_str,
const char *result_str)
{
gpg_error_t err;
void *scalar = NULL;
void *point = NULL;
size_t buflen;
unsigned char result[32];
char result_hex[65];
int i;
int algo = GCRY_ECC_CURVE25519;
unsigned int keylen;
if (verbose > 1)
info ("Running test %d\n", testno);
if (!(keylen = gcry_ecc_get_algo_keylen (algo)))
{
fail ("error getting keylen for test %d", testno);
goto leave;
}
if (keylen != 32)
{
fail ("error invalid keylen for test %d", testno);
goto leave;
}
if (!(scalar = hex2buffer (k_str, &buflen)) || buflen != keylen)
{
fail ("error of input for test %d, %s: %s",
testno, "k", "invalid hex string");
goto leave;
}
if (!(point = hex2buffer (u_str, &buflen)) || buflen != keylen)
{
fail ("error of input for test %d, %s: %s",
testno, "u", "invalid hex string");
goto leave;
}
if ((err = gcry_ecc_mul_point (algo, result, scalar, point)))
fail ("gcry_ecc_mul_point failed for test %d: %s", testno,
gpg_strerror (err));
for (i=0; i < keylen; i++)
snprintf (&result_hex[i*2], 3, "%02x", result[i]);
if (strcmp (result_str, result_hex))
{
fail ("gcry_ecc_mul_point failed for test %d: %s",
testno, "wrong value returned");
info (" expected: '%s'", result_str);
info (" got: '%s'", result_hex);
}
leave:
xfree (scalar);
xfree (point);
}
static void
test_cv (int testno, const char *k_str, const char *u_str,
const char *result_str)
{
test_cv_hl (testno, k_str, u_str, result_str);
test_cv_x25519 (testno, k_str, u_str, result_str);
}
/*
* Test iterative X25519 computation through lower layer MPI routines.
*
* Input: K (as hex string), ITER, R (as hex string)
*
* where R is expected result of iterating X25519 by ITER times.
*
*/
static void
test_it (int testno, const char *k_str, int iter, const char *result_str)
{
gcry_ctx_t ctx;
gpg_error_t err;
void *buffer = NULL;
size_t buflen;
gcry_mpi_t mpi_k = NULL;
gcry_mpi_t mpi_x = NULL;
gcry_mpi_point_t P = NULL;
gcry_mpi_point_t Q;
int i;
gcry_mpi_t mpi_kk = NULL;
if (verbose > 1)
info ("Running test %d: iteration=%d\n", testno, iter);
gcry_mpi_ec_new (&ctx, NULL, "Curve25519");
Q = gcry_mpi_point_new (0);
if (!(buffer = hex2buffer (k_str, &buflen)) || buflen != 32)
{
fail ("error scanning MPI for test %d, %s: %s",
testno, "k", "invalid hex string");
goto leave;
}
reverse_buffer (buffer, buflen);
if ((err = gcry_mpi_scan (&mpi_x, GCRYMPI_FMT_USG, buffer, buflen, NULL)))
{
fail ("error scanning MPI for test %d, %s: %s",
testno, "x", gpg_strerror (err));
goto leave;
}
xfree (buffer);
buffer = NULL;
P = gcry_mpi_point_set (NULL, mpi_x, NULL, GCRYMPI_CONST_ONE);
mpi_k = gcry_mpi_copy (mpi_x);
if (debug)
print_mpi ("k", mpi_k);
for (i = 0; i < iter; i++)
{
/*
* Another variant of decodeScalar25519 thing.
*/
mpi_kk = gcry_mpi_set (mpi_kk, mpi_k);
gcry_mpi_set_bit (mpi_kk, 254);
gcry_mpi_clear_bit (mpi_kk, 255);
gcry_mpi_clear_bit (mpi_kk, 0);
gcry_mpi_clear_bit (mpi_kk, 1);
gcry_mpi_clear_bit (mpi_kk, 2);
gcry_mpi_ec_mul (Q, mpi_kk, P, ctx);
P = gcry_mpi_point_set (P, mpi_k, NULL, GCRYMPI_CONST_ONE);
gcry_mpi_ec_get_affine (mpi_k, NULL, Q, ctx);
if (debug)
print_mpi ("k", mpi_k);
}
{
unsigned char res[32];
char *r, *r0;
gcry_mpi_print (GCRYMPI_FMT_USG, res, 32, NULL, mpi_k);
reverse_buffer (res, 32);
r0 = r = xmalloc (65);
if (!r0)
{
fail ("memory allocation for test %d", testno);
goto leave;
}
for (i=0; i < 32; i++, r += 2)
snprintf (r, 3, "%02x", res[i]);
if (strcmp (result_str, r0))
{
fail ("curv25519 failed for test %d: %s",
testno, "wrong value returned");
info (" expected: '%s'", result_str);
info (" got: '%s'", r0);
}
xfree (r0);
}
leave:
gcry_mpi_release (mpi_kk);
gcry_mpi_release (mpi_k);
gcry_mpi_point_release (P);
gcry_mpi_release (mpi_x);
xfree (buffer);
gcry_mpi_point_release (Q);
gcry_ctx_release (ctx);
}
/*
* X-coordinate of generator of the Curve25519.
*/
#define G_X "0900000000000000000000000000000000000000000000000000000000000000"
/*
* Test Diffie-Hellman in RFC-7748.
*
* Note that it's not like the ECDH of OpenPGP, where we use
* ephemeral public key.
*/
static void
test_dh (int testno, const char *a_priv_str, const char *a_pub_str,
const char *b_priv_str, const char *b_pub_str,
const char *result_str)
{
/* Test A for private key corresponds to public key. */
test_cv (testno, a_priv_str, G_X, a_pub_str);
/* Test B for private key corresponds to public key. */
test_cv (testno, b_priv_str, G_X, b_pub_str);
/* Test DH with A's private key and B's public key. */
test_cv (testno, a_priv_str, b_pub_str, result_str);
/* Test DH with B's private key and A's public key. */
test_cv (testno, b_priv_str, a_pub_str, result_str);
}
static void
check_cv25519 (void)
{
int ntests;
info ("Checking Curve25519.\n");
ntests = 0;
/*
* Values are cited from RFC-7748: 5.2. Test Vectors.
* Following two tests are for the first type test.
*/
test_cv (1,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"e6db6867583030db3594c1a424b15f7c726624ec26b3353b10a903a6d0ab1c4c",
"c3da55379de9c6908e94ea4df28d084f32eccf03491c71f754b4075577a28552");
ntests++;
test_cv (2,
"4b66e9d4d1b4673c5ad22691957d6af5c11b6421e0ea01d42ca4169e7918ba0d",
"e5210f12786811d3f4b7959d0538ae2c31dbe7106fc03c3efc4cd549c715a493",
"95cbde9476e8907d7aade45cb4b873f88b595a68799fa152e6f8f7647aac7957");
ntests++;
/*
* Additional test. Value is from second type test.
*/
test_cv (3,
G_X,
G_X,
"422c8e7a6227d7bca1350b3e2bb7279f7897b87bb6854b783c60e80311ae3079");
ntests++;
/*
* Following two tests are for the second type test,
* with one iteration and 1,000 iterations. (1,000,000 iterations
* takes too long.)
*/
test_it (4,
G_X,
1,
"422c8e7a6227d7bca1350b3e2bb7279f7897b87bb6854b783c60e80311ae3079");
ntests++;
test_it (5,
G_X,
1000,
"684cf59ba83309552800ef566f2f4d3c1c3887c49360e3875f2eb94d99532c51");
ntests++;
/*
* Last test is from: 6. Diffie-Hellman, 6.1. Curve25519
*/
test_dh (6,
/* Alice's private key, a */
"77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a",
/* Alice's public key, X25519(a, 9) */
"8520f0098930a754748b7ddcb43ef75a0dbf3a0d26381af4eba4a98eaa9b4e6a",
/* Bob's private key, b */
"5dab087e624a8a4b79e17f8b83800ee66f3bb1292618b6fd1c2f8b27ff88e0eb",
/* Bob's public key, X25519(b, 9) */
"de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f",
/* Their shared secret, K */
"4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742");
ntests++;
/* Seven tests which results 0. */
test_cv (7,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"0000000000000000000000000000000000000000000000000000000000000000",
"0000000000000000000000000000000000000000000000000000000000000000");
ntests++;
test_cv (8,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"0100000000000000000000000000000000000000000000000000000000000000",
"0000000000000000000000000000000000000000000000000000000000000000");
ntests++;
test_cv (9,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"e0eb7a7c3b41b8ae1656e3faf19fc46ada098deb9c32b1fd866205165f49b800",
"0000000000000000000000000000000000000000000000000000000000000000");
ntests++;
test_cv (10,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"5f9c95bca3508c24b1d0b1559c83ef5b04445cc4581c8e86d8224eddd09f1157",
"0000000000000000000000000000000000000000000000000000000000000000");
ntests++;
test_cv (11,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"ecffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
"0000000000000000000000000000000000000000000000000000000000000000");
ntests++;
test_cv (12,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"edffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
"0000000000000000000000000000000000000000000000000000000000000000");
ntests++;
test_cv (13,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"eeffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff7f",
"0000000000000000000000000000000000000000000000000000000000000000");
ntests++;
/* Five tests which resulted 0 if decodeUCoordinate didn't change MSB. */
test_cv (14,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"cdeb7a7c3b41b8ae1656e3faf19fc46ada098deb9c32b1fd866205165f49b880",
"7ce548bc4919008436244d2da7a9906528fe3a6d278047654bd32d8acde9707b");
ntests++;
test_cv (15,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"4c9c95bca3508c24b1d0b1559c83ef5b04445cc4581c8e86d8224eddd09f11d7",
"e17902e989a034acdf7248260e2c94cdaf2fe1e72aaac7024a128058b6189939");
ntests++;
test_cv (16,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"d9ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
"ea6e6ddf0685c31e152d5818441ac9ac8db1a01f3d6cb5041b07443a901e7145");
ntests++;
test_cv (17,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"daffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
"845ddce7b3a9b3ee01a2f1fd4282ad293310f7a232cbc5459fb35d94bccc9d05");
ntests++;
test_cv (18,
"a546e36bf0527c9d3b16154b82465edd62144c0ac1fc5a18506a2244ba449ac4",
"dbffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff",
"6989e2cb1cea159acf121b0af6bf77493189c9bd32c2dac71669b540f9488247");
ntests++;
if (ntests != N_TESTS)
fail ("did %d tests but expected %d", ntests, N_TESTS);
else if ((ntests % 256))
show_note ("%d tests done\n", ntests);
}
int
main (int argc, char **argv)
{
int last_argc = -1;
if (argc)
{ argc--; argv++; }
while (argc && last_argc != argc )
{
last_argc = argc;
if (!strcmp (*argv, "--"))
{
argc--; argv++;
break;
}
else if (!strcmp (*argv, "--help"))
{
fputs ("usage: " PGM " [options]\n"
"Options:\n"
" --verbose print timings etc.\n"
" --debug flyswatter\n",
stdout);
exit (0);
}
else if (!strcmp (*argv, "--verbose"))
{
verbose++;
argc--; argv++;
}
else if (!strcmp (*argv, "--debug"))
{
verbose += 2;
debug++;
argc--; argv++;
}
else if (!strncmp (*argv, "--", 2))
die ("unknown option '%s'", *argv);
}
xgcry_control ((GCRYCTL_DISABLE_SECMEM, 0));
if (!gcry_check_version (GCRYPT_VERSION))
die ("version mismatch\n");
if (debug)
xgcry_control ((GCRYCTL_SET_DEBUG_FLAGS, 1u , 0));
xgcry_control ((GCRYCTL_ENABLE_QUICK_RANDOM, 0));
xgcry_control ((GCRYCTL_INITIALIZATION_FINISHED, 0));
start_timer ();
check_cv25519 ();
stop_timer ();
info ("All tests completed in %s. Errors: %d\n",
elapsed_time (1), error_count);
return !!error_count;
}