forked from gost-engine/engine
/
gost_ec_sign.c
522 lines (474 loc) · 13.7 KB
/
gost_ec_sign.c
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/**********************************************************************
* gost_ec_sign.c *
* Copyright (c) 2005-2013 Cryptocom LTD *
* This file is distributed under the same license as OpenSSL *
* *
* Implementation of GOST R 34.10-2001 *
* Requires OpenSSL 1.0.0+ for compilation *
**********************************************************************/
#include "gost_lcl.h"
#include <string.h>
#include <openssl/rand.h>
#include <openssl/ecdsa.h>
#include <openssl/err.h>
#include "e_gost_err.h"
#ifdef DEBUG_SIGN
extern
void dump_signature(const char *message, const unsigned char *buffer,
size_t len);
void dump_dsa_sig(const char *message, DSA_SIG *sig);
#else
# define dump_signature(a,b,c)
# define dump_dsa_sig(a,b)
#endif
/* Convert little-endian byte array into bignum */
BIGNUM *hashsum2bn(const unsigned char *dgst, int len)
{
unsigned char buf[64];
int i;
if (len > sizeof(buf))
return NULL;
for (i = 0; i < len; i++) {
buf[len - i - 1] = dgst[i];
}
return getbnfrombuf(buf, len);
}
static R3410_ec_params *gost_nid2params(int nid)
{
R3410_ec_params *params;
/* Search nid in 2012 paramset */
params = R3410_2012_512_paramset;
while (params->nid != NID_undef) {
if (params->nid == nid)
return params;
params++;
}
/* Search nid in 2001 paramset */
params = R3410_2001_paramset;
while (params->nid != NID_undef) {
if (params->nid == nid)
return params;
params++;
}
return NULL;
}
/*
* Fills EC_KEY structure hidden in the app_data field of DSA structure
* with parameter information, extracted from parameter array in
* params.c file.
*
* Also fils DSA->q field with copy of EC_GROUP order field to make
* DSA_size function work
*/
int fill_GOST_EC_params(EC_KEY *eckey, int nid)
{
R3410_ec_params *params = gost_nid2params(nid);
EC_GROUP *grp = NULL;
EC_POINT *P = NULL;
BIGNUM *p = NULL, *q = NULL, *a = NULL, *b = NULL, *x = NULL, *y = NULL;
BN_CTX *ctx;
int ok = 0;
if (!eckey || !params) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, GOST_R_UNSUPPORTED_PARAMETER_SET);
return 0;
}
if (!(ctx = BN_CTX_new())) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_MALLOC_FAILURE);
return 0;
}
BN_CTX_start(ctx);
p = BN_CTX_get(ctx);
a = BN_CTX_get(ctx);
b = BN_CTX_get(ctx);
x = BN_CTX_get(ctx);
y = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
if (!p || !a || !b || !x || !y || !q) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_MALLOC_FAILURE);
goto end;
}
if (!BN_hex2bn(&p, params->p)
|| !BN_hex2bn(&a, params->a)
|| !BN_hex2bn(&b, params->b)) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_INTERNAL_ERROR);
goto end;
}
grp = EC_GROUP_new_curve_GFp(p, a, b, ctx);
if (!grp) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_MALLOC_FAILURE);
goto end;
}
P = EC_POINT_new(grp);
if (!P) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_MALLOC_FAILURE);
goto end;
}
if (!BN_hex2bn(&x, params->x)
|| !BN_hex2bn(&y, params->y)
|| !EC_POINT_set_affine_coordinates_GFp(grp, P, x, y, ctx)
|| !BN_hex2bn(&q, params->q)) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_INTERNAL_ERROR);
goto end;
}
if (!EC_GROUP_set_generator(grp, P, q, NULL)) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_INTERNAL_ERROR);
goto end;
}
EC_GROUP_set_curve_name(grp, params->nid);
if (!EC_KEY_set_group(eckey, grp)) {
GOSTerr(GOST_F_FILL_GOST_EC_PARAMS, ERR_R_INTERNAL_ERROR);
goto end;
}
ok = 1;
end:
if (P)
EC_POINT_free(P);
if (grp)
EC_GROUP_free(grp);
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ok;
}
/*
* Computes gost_ec signature as DSA_SIG structure
*
*/
DSA_SIG *gost_ec_sign(const unsigned char *dgst, int dlen, EC_KEY *eckey)
{
DSA_SIG *newsig = NULL, *ret = NULL;
BIGNUM *md = NULL;
BIGNUM *order = NULL;
const EC_GROUP *group;
const BIGNUM *priv_key;
BIGNUM *r = NULL, *s = NULL, *X = NULL, *tmp = NULL, *tmp2 = NULL,
*k = NULL, *e = NULL;
EC_POINT *C = NULL;
BN_CTX *ctx;
OPENSSL_assert(dgst != NULL && eckey != NULL);
if (!(ctx = BN_CTX_new())) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_MALLOC_FAILURE);
return NULL;
}
BN_CTX_start(ctx);
OPENSSL_assert(dlen == 32 || dlen == 64);
md = hashsum2bn(dgst, dlen);
newsig = DSA_SIG_new();
if (!newsig || !md) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_MALLOC_FAILURE);
goto err;
}
group = EC_KEY_get0_group(eckey);
if (!group) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_INTERNAL_ERROR);
goto err;
}
order = BN_CTX_get(ctx);
if (!order || !EC_GROUP_get_order(group, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_INTERNAL_ERROR);
goto err;
}
priv_key = EC_KEY_get0_private_key(eckey);
if (!priv_key) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_INTERNAL_ERROR);
goto err;
}
e = BN_CTX_get(ctx);
if (!e || !BN_mod(e, md, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_INTERNAL_ERROR);
goto err;
}
#ifdef DEBUG_SIGN
fprintf(stderr, "digest as bignum=");
BN_print_fp(stderr, md);
fprintf(stderr, "\ndigest mod q=");
BN_print_fp(stderr, e);
fprintf(stderr, "\n");
#endif
if (BN_is_zero(e)) {
BN_one(e);
}
k = BN_CTX_get(ctx);
C = EC_POINT_new(group);
if (!k || !C) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_MALLOC_FAILURE);
goto err;
}
do {
do {
if (!BN_rand_range(k, order)) {
GOSTerr(GOST_F_GOST_EC_SIGN, GOST_R_RNG_ERROR);
goto err;
}
/*
* To avoid timing information leaking the length of k,
* compute C*k using an equivalent scalar of fixed bit-length */
if (!BN_add(k, k, order)
|| (BN_num_bits(k) <= BN_num_bits(order)
&& !BN_add(k, k, order))) {
goto err;
}
if (!EC_POINT_mul(group, C, k, NULL, NULL, ctx)) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_EC_LIB);
goto err;
}
if (!X)
X = BN_CTX_get(ctx);
if (!r)
r = BN_CTX_get(ctx);
if (!X || !r) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_get_affine_coordinates_GFp(group, C, X, NULL, ctx)) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_EC_LIB);
goto err;
}
if (!BN_nnmod(r, X, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_INTERNAL_ERROR);
goto err;
}
}
while (BN_is_zero(r));
/* s = (r*priv_key+k*e) mod order */
if (!tmp)
tmp = BN_CTX_get(ctx);
if (!tmp2)
tmp2 = BN_CTX_get(ctx);
if (!s)
s = BN_CTX_get(ctx);
if (!tmp || !tmp2 || !s) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!BN_mod_mul(tmp, priv_key, r, order, ctx)
|| !BN_mod_mul(tmp2, k, e, order, ctx)
|| !BN_mod_add(s, tmp, tmp2, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_INTERNAL_ERROR);
goto err;
}
}
while (BN_is_zero(s));
newsig->s = BN_dup(s);
newsig->r = BN_dup(r);
if (!newsig->s || !newsig->r) {
GOSTerr(GOST_F_GOST_EC_SIGN, ERR_R_MALLOC_FAILURE);
goto err;
}
ret = newsig;
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
if (C)
EC_POINT_free(C);
if (md)
BN_free(md);
if (!ret && newsig) {
DSA_SIG_free(newsig);
}
return ret;
}
/*
* Verifies gost ec signature
*
*/
int gost_ec_verify(const unsigned char *dgst, int dgst_len,
DSA_SIG *sig, EC_KEY *ec)
{
BN_CTX *ctx;
const EC_GROUP *group = (ec) ? EC_KEY_get0_group(ec) : NULL;
BIGNUM *order;
BIGNUM *md = NULL, *e = NULL, *R = NULL, *v = NULL,
*z1 = NULL, *z2 = NULL;
BIGNUM *X = NULL, *tmp = NULL;
EC_POINT *C = NULL;
const EC_POINT *pub_key = NULL;
int ok = 0;
OPENSSL_assert(dgst != NULL && sig != NULL && group != NULL);
if (!(ctx = BN_CTX_new())) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_MALLOC_FAILURE);
return 0;
}
BN_CTX_start(ctx);
order = BN_CTX_get(ctx);
e = BN_CTX_get(ctx);
z1 = BN_CTX_get(ctx);
z2 = BN_CTX_get(ctx);
tmp = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
R = BN_CTX_get(ctx);
v = BN_CTX_get(ctx);
if (!order || !e || !z1 || !z2 || !tmp || !X || !R || !v) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_MALLOC_FAILURE);
goto err;
}
pub_key = EC_KEY_get0_public_key(ec);
if (!pub_key || !EC_GROUP_get_order(group, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_INTERNAL_ERROR);
goto err;
}
if (BN_is_zero(sig->s) || BN_is_zero(sig->r) ||
(BN_cmp(sig->s, order) >= 1) || (BN_cmp(sig->r, order) >= 1)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, GOST_R_SIGNATURE_PARTS_GREATER_THAN_Q);
goto err;
}
OPENSSL_assert(dgst_len == 32 || dgst_len == 64);
md = hashsum2bn(dgst, dgst_len);
if (!md || !BN_mod(e, md, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_INTERNAL_ERROR);
goto err;
}
#ifdef DEBUG_SIGN
fprintf(stderr, "digest as bignum: ");
BN_print_fp(stderr, md);
fprintf(stderr, "\ndigest mod q: ");
BN_print_fp(stderr, e);
#endif
if (BN_is_zero(e) && !BN_one(e)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_INTERNAL_ERROR);
goto err;
}
v = BN_mod_inverse(v, e, order, ctx);
if (!v || !BN_mod_mul(z1, sig->s, v, order, ctx)
|| !BN_sub(tmp, order, sig->r)
|| !BN_mod_mul(z2, tmp, v, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_INTERNAL_ERROR);
goto err;
}
#ifdef DEBUG_SIGN
fprintf(stderr, "\nInverted digest value: ");
BN_print_fp(stderr, v);
fprintf(stderr, "\nz1: ");
BN_print_fp(stderr, z1);
fprintf(stderr, "\nz2: ");
BN_print_fp(stderr, z2);
#endif
C = EC_POINT_new(group);
if (!C) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, C, z1, pub_key, z2, ctx)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_get_affine_coordinates_GFp(group, C, X, NULL, ctx)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_EC_LIB);
goto err;
}
if (!BN_mod(R, X, order, ctx)) {
GOSTerr(GOST_F_GOST_EC_VERIFY, ERR_R_INTERNAL_ERROR);
goto err;
}
#ifdef DEBUG_SIGN
fprintf(stderr, "\nX=");
BN_print_fp(stderr, X);
fprintf(stderr, "\nX mod q=");
BN_print_fp(stderr, R);
fprintf(stderr, "\n");
#endif
if (BN_cmp(R, sig->r) != 0) {
GOSTerr(GOST_F_GOST_EC_VERIFY, GOST_R_SIGNATURE_MISMATCH);
} else {
ok = 1;
}
err:
if (C)
EC_POINT_free(C);
BN_CTX_end(ctx);
BN_CTX_free(ctx);
if (md)
BN_free(md);
return ok;
}
/*
* Computes GOST R 34.10-2001 public key
* or GOST R 34.10-2012 public key
*
*/
int gost_ec_compute_public(EC_KEY *ec)
{
const EC_GROUP *group = (ec) ? EC_KEY_get0_group(ec) : NULL;
EC_POINT *pub_key = NULL;
const BIGNUM *priv_key = NULL;
BN_CTX *ctx = NULL;
int ok = 0;
if (!group) {
GOSTerr(GOST_F_GOST_EC_COMPUTE_PUBLIC, GOST_R_KEY_IS_NOT_INITIALIZED);
return 0;
}
ctx = BN_CTX_new();
if (!ctx) {
GOSTerr(GOST_F_GOST_EC_COMPUTE_PUBLIC, ERR_R_MALLOC_FAILURE);
return 0;
}
BN_CTX_start(ctx);
priv_key = EC_KEY_get0_private_key(ec);
if (!priv_key) {
GOSTerr(GOST_F_GOST_EC_COMPUTE_PUBLIC, ERR_R_EC_LIB);
goto err;
}
pub_key = EC_POINT_new(group);
if (!pub_key) {
GOSTerr(GOST_F_GOST_EC_COMPUTE_PUBLIC, ERR_R_MALLOC_FAILURE);
goto err;
}
if (!EC_POINT_mul(group, pub_key, priv_key, NULL, NULL, ctx)) {
GOSTerr(GOST_F_GOST_EC_COMPUTE_PUBLIC, ERR_R_EC_LIB);
goto err;
}
if (!EC_KEY_set_public_key(ec, pub_key)) {
GOSTerr(GOST_F_GOST_EC_COMPUTE_PUBLIC, ERR_R_EC_LIB);
goto err;
}
ok = 1;
err:
if (pub_key)
EC_POINT_free(pub_key);
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ok;
}
/*
*
* Generates GOST R 34.10-2001
* or GOST R 34.10-2012 keypair
*
*/
int gost_ec_keygen(EC_KEY *ec)
{
BIGNUM *order = NULL, *d = NULL;
const EC_GROUP *group = (ec) ? EC_KEY_get0_group(ec) : NULL;
int ok = 0;
if (!group) {
GOSTerr(GOST_F_GOST_EC_KEYGEN, ERR_R_INTERNAL_ERROR);
return 0;
}
order = BN_new();
d = BN_new();
if (!order || !d) {
GOSTerr(GOST_F_GOST_EC_KEYGEN, ERR_R_MALLOC_FAILURE);
goto end;
}
if (!EC_GROUP_get_order(group, order, NULL)) {
GOSTerr(GOST_F_GOST_EC_KEYGEN, ERR_R_INTERNAL_ERROR);
goto end;
}
do {
if (!BN_rand_range(d, order)) {
GOSTerr(GOST_F_GOST_EC_KEYGEN, GOST_R_RNG_ERROR);
goto end;
}
}
while (BN_is_zero(d));
if (!EC_KEY_set_private_key(ec, d)) {
GOSTerr(GOST_F_GOST_EC_KEYGEN, ERR_R_INTERNAL_ERROR);
goto end;
}
ok = 1;
end:
if (d)
BN_free(d);
if (order)
BN_free(order);
return (ok) ? gost_ec_compute_public(ec) : 0;
}