openssl/engines/ccgost/gost2001.c

341 lines
7.8 KiB
C

/**********************************************************************
* gost2001.c *
* Copyright (c) 2005-2006 Cryptocom LTD *
* This file is distributed under the same license as OpenSSL *
* *
* Implementation of GOST R 34.10-2001 *
* Requires OpenSSL 0.9.9 for compilation *
**********************************************************************/
#include "gost_lcl.h"
#include "gost_params.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
/*
* 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_GOST2001_params(EC_KEY *eckey, int nid)
{
R3410_2001_params *params = R3410_2001_paramset;
EC_GROUP *grp=NULL;
BIGNUM *p=NULL,*q=NULL,*a=NULL,*b=NULL,*x=NULL,*y=NULL;
EC_POINT *P=NULL;
BN_CTX *ctx=BN_CTX_new();
int ok=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);
while (params->nid!=NID_undef && params->nid != nid) params++;
if (params->nid == NID_undef)
{
GOSTerr(GOST_F_FILL_GOST2001_PARAMS,GOST_R_UNSUPPORTED_PARAMETER_SET);
goto err;
}
BN_hex2bn(&p,params->p);
BN_hex2bn(&a,params->a);
BN_hex2bn(&b,params->b);
grp = EC_GROUP_new_curve_GFp(p,a,b,ctx);
P = EC_POINT_new(grp);
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);
#ifdef DEBUG_KEYS
fprintf(stderr,"Set params index %d oid %s\nq=",
(params-R3410_2001_paramset),OBJ_nid2sn(params->nid));
BN_print_fp(stderr,q);
fprintf(stderr,"\n");
#endif
EC_GROUP_set_generator(grp,P,q,NULL);
EC_GROUP_set_curve_name(grp,params->nid);
EC_KEY_set_group(eckey,grp);
ok=1;
err:
EC_POINT_free(P);
EC_GROUP_free(grp);
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ok;
}
/*
* Computes gost2001 signature as DSA_SIG structure
*
*
*/
DSA_SIG *gost2001_do_sign(const unsigned char *dgst,int dlen, EC_KEY *eckey)
{
DSA_SIG *newsig = NULL;
BIGNUM *md = hashsum2bn(dgst);
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 = BN_CTX_new();
BN_CTX_start(ctx);
OPENSSL_assert(dlen==32);
newsig=DSA_SIG_new();
if (!newsig)
{
GOSTerr(GOST_F_GOST2001_DO_SIGN,GOST_R_NO_MEMORY);
goto err;
}
group = EC_KEY_get0_group(eckey);
order=BN_CTX_get(ctx);
EC_GROUP_get_order(group,order,ctx);
priv_key = EC_KEY_get0_private_key(eckey);
e = BN_CTX_get(ctx);
BN_mod(e,md,order,ctx);
#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);
do
{
do
{
if (!BN_rand_range(k,order))
{
GOSTerr(GOST_F_GOST2001_DO_SIGN,GOST_R_RANDOM_NUMBER_GENERATOR_FAILED);
DSA_SIG_free(newsig);
goto err;
}
if (!EC_POINT_mul(group,C,k,NULL,NULL,ctx))
{
GOSTerr(GOST_F_GOST2001_DO_SIGN,ERR_R_EC_LIB);
DSA_SIG_free(newsig);
goto err;
}
if (!X) X=BN_CTX_get(ctx);
if (!EC_POINT_get_affine_coordinates_GFp(group,C,X,NULL,ctx))
{
GOSTerr(GOST_F_GOST2001_DO_SIGN,ERR_R_EC_LIB);
DSA_SIG_free(newsig);
goto err;
}
if (!r) r=BN_CTX_get(ctx);
BN_nnmod(r,X,order,ctx);
}
while (BN_is_zero(r));
/* s = (r*priv_key+k*e) mod order */
if (!tmp) tmp = BN_CTX_get(ctx);
BN_mod_mul(tmp,priv_key,r,order,ctx);
if (!tmp2) tmp2 = BN_CTX_get(ctx);
BN_mod_mul(tmp2,k,e,order,ctx);
if (!s) s=BN_CTX_get(ctx);
BN_mod_add(s,tmp,tmp2,order,ctx);
}
while (BN_is_zero(s));
newsig->s=BN_dup(s);
newsig->r=BN_dup(r);
err:
BN_CTX_end(ctx);
BN_CTX_free(ctx);
EC_POINT_free(C);
BN_free(md);
return newsig;
}
/*
* Verifies gost 2001 signature
*
*/
int gost2001_do_verify(const unsigned char *dgst,int dgst_len,
DSA_SIG *sig, EC_KEY *ec)
{
BN_CTX *ctx=BN_CTX_new();
const EC_GROUP *group = EC_KEY_get0_group(ec);
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;
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);
EC_GROUP_get_order(group,order,ctx);
pub_key = EC_KEY_get0_public_key(ec);
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_GOST2001_DO_VERIFY,GOST_R_SIGNATURE_PARTS_GREATER_THAN_Q);
goto err;
}
md = hashsum2bn(dgst);
BN_mod(e,md,order,ctx);
#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);
v=BN_mod_inverse(v,e,order,ctx);
BN_mod_mul(z1,sig->s,v,order,ctx);
BN_sub(tmp,order,sig->r);
BN_mod_mul(z2,tmp,v,order,ctx);
#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 (!EC_POINT_mul(group,C,z1,pub_key,z2,ctx))
{
GOSTerr(GOST_F_GOST2001_DO_VERIFY,ERR_R_EC_LIB);
goto err;
}
if (!EC_POINT_get_affine_coordinates_GFp(group,C,X,NULL,ctx))
{
GOSTerr(GOST_F_GOST2001_DO_VERIFY,ERR_R_EC_LIB);
goto err;
}
BN_mod(R,X,order,ctx);
#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_GOST2001_DO_VERIFY,GOST_R_SIGNATURE_MISMATCH);
}
else
{
ok = 1;
}
err:
EC_POINT_free(C);
BN_CTX_end(ctx);
BN_CTX_free(ctx);
BN_free(md);
return ok;
}
/*
* Computes GOST R 34.10-2001 public key
*
*
*/
int gost2001_compute_public(EC_KEY *ec)
{
const EC_GROUP *group = EC_KEY_get0_group(ec);
EC_POINT *pub_key=NULL;
const BIGNUM *priv_key=NULL;
BN_CTX *ctx=NULL;
int ok=0;
if (!group)
{
GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,GOST_R_KEY_IS_NOT_INITIALIZED);
return 0;
}
ctx=BN_CTX_new();
BN_CTX_start(ctx);
if (!(priv_key=EC_KEY_get0_private_key(ec)))
{
GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,ERR_R_EC_LIB);
goto err;
}
pub_key = EC_POINT_new(group);
if (!EC_POINT_mul(group,pub_key,priv_key,NULL,NULL,ctx))
{
GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,ERR_R_EC_LIB);
goto err;
}
if (!EC_KEY_set_public_key(ec,pub_key))
{
GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,ERR_R_EC_LIB);
goto err;
}
ok = 256;
err:
BN_CTX_end(ctx);
EC_POINT_free(pub_key);
BN_CTX_free(ctx);
return ok;
}
/*
*
* Generates GOST R 34.10-2001 keypair
*
*
*/
int gost2001_keygen(EC_KEY *ec)
{
BIGNUM *order = BN_new(),*d=BN_new();
const EC_GROUP *group = EC_KEY_get0_group(ec);
EC_GROUP_get_order(group,order,NULL);
do
{
if (!BN_rand_range(d,order))
{
GOSTerr(GOST_F_GOST2001_KEYGEN,GOST_R_RANDOM_NUMBER_GENERATOR_FAILED);
BN_free(d);
BN_free(order);
return 0;
}
}
while (BN_is_zero(d));
EC_KEY_set_private_key(ec,d);
BN_free(d);
BN_free(order);
return gost2001_compute_public(ec);
}