343 lines
7.9 KiB
C
343 lines
7.9 KiB
C
/**********************************************************************
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* gost2001.c *
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* Copyright (c) 2005-2006 Cryptocom LTD *
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* This file is distributed under the same license as OpenSSL *
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* *
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* Implementation of GOST R 34.10-2001 *
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* Requires OpenSSL 0.9.9 for compilation *
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**********************************************************************/
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#include "gost_lcl.h"
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#include "gost_params.h"
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#include <string.h>
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#include <openssl/rand.h>
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#include <openssl/ecdsa.h>
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#include <openssl/err.h>
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#include "e_gost_err.h"
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#ifdef DEBUG_SIGN
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extern
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void dump_signature(const char *message,const unsigned char *buffer,size_t len);
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void dump_dsa_sig(const char *message, DSA_SIG *sig);
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#else
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#define dump_signature(a,b,c)
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#define dump_dsa_sig(a,b)
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#endif
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/*
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* Fills EC_KEY structure hidden in the app_data field of DSA structure
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* with parameter information, extracted from parameter array in
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* params.c file.
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*
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* Also fils DSA->q field with copy of EC_GROUP order field to make
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* DSA_size function work
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*/
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int fill_GOST2001_params(EC_KEY *eckey, int nid)
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{
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R3410_2001_params *params = R3410_2001_paramset;
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EC_GROUP *grp=NULL;
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BIGNUM *p=NULL,*q=NULL,*a=NULL,*b=NULL,*x=NULL,*y=NULL;
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EC_POINT *P=NULL;
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BN_CTX *ctx=BN_CTX_new();
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int ok=0;
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BN_CTX_start(ctx);
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p=BN_CTX_get(ctx);
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a=BN_CTX_get(ctx);
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b=BN_CTX_get(ctx);
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x=BN_CTX_get(ctx);
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y=BN_CTX_get(ctx);
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q=BN_CTX_get(ctx);
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while (params->nid!=NID_undef && params->nid != nid) params++;
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if (params->nid == NID_undef)
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{
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GOSTerr(GOST_F_FILL_GOST2001_PARAMS,GOST_R_UNSUPPORTED_PARAMETER_SET);
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goto err;
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}
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BN_hex2bn(&p,params->p);
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BN_hex2bn(&a,params->a);
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BN_hex2bn(&b,params->b);
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grp = EC_GROUP_new_curve_GFp(p,a,b,ctx);
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P = EC_POINT_new(grp);
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BN_hex2bn(&x,params->x);
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BN_hex2bn(&y,params->y);
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EC_POINT_set_affine_coordinates_GFp(grp,P,x,y,ctx);
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BN_hex2bn(&q,params->q);
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#ifdef DEBUG_KEYS
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fprintf(stderr,"Set params index %d oid %s\nq=",
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(params-R3410_2001_paramset),OBJ_nid2sn(params->nid));
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BN_print_fp(stderr,q);
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fprintf(stderr,"\n");
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#endif
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EC_GROUP_set_generator(grp,P,q,NULL);
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EC_GROUP_set_curve_name(grp,params->nid);
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EC_KEY_set_group(eckey,grp);
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ok=1;
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err:
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EC_POINT_free(P);
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EC_GROUP_free(grp);
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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return ok;
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}
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/*
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* Computes gost2001 signature as DSA_SIG structure
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*
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*
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*/
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DSA_SIG *gost2001_do_sign(const unsigned char *dgst,int dlen, EC_KEY *eckey)
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{
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DSA_SIG *newsig = NULL;
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BIGNUM *md = hashsum2bn(dgst);
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BIGNUM *order = NULL;
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const EC_GROUP *group;
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const BIGNUM *priv_key;
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BIGNUM *r=NULL,*s=NULL,*X=NULL,*tmp=NULL,*tmp2=NULL, *k=NULL,*e=NULL;
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EC_POINT *C=NULL;
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BN_CTX *ctx = BN_CTX_new();
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BN_CTX_start(ctx);
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OPENSSL_assert(dlen==32);
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newsig=DSA_SIG_new();
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if (!newsig)
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{
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GOSTerr(GOST_F_GOST2001_DO_SIGN,GOST_R_NO_MEMORY);
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goto err;
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}
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group = EC_KEY_get0_group(eckey);
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order=BN_CTX_get(ctx);
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EC_GROUP_get_order(group,order,ctx);
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priv_key = EC_KEY_get0_private_key(eckey);
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e = BN_CTX_get(ctx);
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BN_mod(e,md,order,ctx);
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#ifdef DEBUG_SIGN
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fprintf(stderr,"digest as bignum=");
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BN_print_fp(stderr,md);
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fprintf(stderr,"\ndigest mod q=");
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BN_print_fp(stderr,e);
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fprintf(stderr,"\n");
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#endif
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if (BN_is_zero(e))
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{
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BN_one(e);
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}
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k =BN_CTX_get(ctx);
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C=EC_POINT_new(group);
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do
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{
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do
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{
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if (!BN_rand_range(k,order))
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{
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GOSTerr(GOST_F_GOST2001_DO_SIGN,GOST_R_RANDOM_NUMBER_GENERATOR_FAILED);
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DSA_SIG_free(newsig);
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newsig = NULL;
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goto err;
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}
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if (!EC_POINT_mul(group,C,k,NULL,NULL,ctx))
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{
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GOSTerr(GOST_F_GOST2001_DO_SIGN,ERR_R_EC_LIB);
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DSA_SIG_free(newsig);
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newsig = NULL;
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goto err;
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}
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if (!X) X=BN_CTX_get(ctx);
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if (!EC_POINT_get_affine_coordinates_GFp(group,C,X,NULL,ctx))
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{
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GOSTerr(GOST_F_GOST2001_DO_SIGN,ERR_R_EC_LIB);
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DSA_SIG_free(newsig);
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newsig = NULL;
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goto err;
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}
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if (!r) r=BN_CTX_get(ctx);
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BN_nnmod(r,X,order,ctx);
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}
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while (BN_is_zero(r));
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/* s = (r*priv_key+k*e) mod order */
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if (!tmp) tmp = BN_CTX_get(ctx);
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BN_mod_mul(tmp,priv_key,r,order,ctx);
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if (!tmp2) tmp2 = BN_CTX_get(ctx);
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BN_mod_mul(tmp2,k,e,order,ctx);
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if (!s) s=BN_CTX_get(ctx);
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BN_mod_add(s,tmp,tmp2,order,ctx);
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}
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while (BN_is_zero(s));
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newsig->s=BN_dup(s);
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newsig->r=BN_dup(r);
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err:
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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EC_POINT_free(C);
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BN_free(md);
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return newsig;
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}
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/*
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* Verifies gost 2001 signature
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*
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*/
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int gost2001_do_verify(const unsigned char *dgst,int dgst_len,
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DSA_SIG *sig, EC_KEY *ec)
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{
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BN_CTX *ctx=BN_CTX_new();
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const EC_GROUP *group = EC_KEY_get0_group(ec);
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BIGNUM *order;
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BIGNUM *md = NULL,*e=NULL,*R=NULL,*v=NULL,*z1=NULL,*z2=NULL;
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BIGNUM *X=NULL,*tmp=NULL;
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EC_POINT *C = NULL;
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const EC_POINT *pub_key=NULL;
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int ok=0;
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BN_CTX_start(ctx);
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order = BN_CTX_get(ctx);
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e = BN_CTX_get(ctx);
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z1 = BN_CTX_get(ctx);
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z2 = BN_CTX_get(ctx);
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tmp = BN_CTX_get(ctx);
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X= BN_CTX_get(ctx);
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R=BN_CTX_get(ctx);
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v=BN_CTX_get(ctx);
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EC_GROUP_get_order(group,order,ctx);
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pub_key = EC_KEY_get0_public_key(ec);
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if (BN_is_zero(sig->s) || BN_is_zero(sig->r) ||
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(BN_cmp(sig->s,order)>=1) || (BN_cmp(sig->r,order)>=1))
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{
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GOSTerr(GOST_F_GOST2001_DO_VERIFY,GOST_R_SIGNATURE_PARTS_GREATER_THAN_Q);
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goto err;
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}
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md = hashsum2bn(dgst);
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BN_mod(e,md,order,ctx);
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#ifdef DEBUG_SIGN
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fprintf(stderr,"digest as bignum: ");
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BN_print_fp(stderr,md);
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fprintf(stderr,"\ndigest mod q: ");
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BN_print_fp(stderr,e);
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#endif
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if (BN_is_zero(e)) BN_one(e);
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v=BN_mod_inverse(v,e,order,ctx);
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BN_mod_mul(z1,sig->s,v,order,ctx);
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BN_sub(tmp,order,sig->r);
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BN_mod_mul(z2,tmp,v,order,ctx);
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#ifdef DEBUG_SIGN
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fprintf(stderr,"\nInverted digest value: ");
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BN_print_fp(stderr,v);
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fprintf(stderr,"\nz1: ");
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BN_print_fp(stderr,z1);
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fprintf(stderr,"\nz2: ");
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BN_print_fp(stderr,z2);
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#endif
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C = EC_POINT_new(group);
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if (!EC_POINT_mul(group,C,z1,pub_key,z2,ctx))
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{
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GOSTerr(GOST_F_GOST2001_DO_VERIFY,ERR_R_EC_LIB);
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goto err;
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}
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if (!EC_POINT_get_affine_coordinates_GFp(group,C,X,NULL,ctx))
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{
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GOSTerr(GOST_F_GOST2001_DO_VERIFY,ERR_R_EC_LIB);
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goto err;
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}
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BN_mod(R,X,order,ctx);
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#ifdef DEBUG_SIGN
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fprintf(stderr,"\nX=");
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BN_print_fp(stderr,X);
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fprintf(stderr,"\nX mod q=");
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BN_print_fp(stderr,R);
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fprintf(stderr,"\n");
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#endif
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if (BN_cmp(R,sig->r)!=0)
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{
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GOSTerr(GOST_F_GOST2001_DO_VERIFY,GOST_R_SIGNATURE_MISMATCH);
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}
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else
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{
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ok = 1;
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}
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err:
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EC_POINT_free(C);
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BN_CTX_end(ctx);
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BN_CTX_free(ctx);
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BN_free(md);
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return ok;
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}
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/*
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* Computes GOST R 34.10-2001 public key
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*
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*
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*/
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int gost2001_compute_public(EC_KEY *ec)
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{
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const EC_GROUP *group = EC_KEY_get0_group(ec);
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EC_POINT *pub_key=NULL;
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const BIGNUM *priv_key=NULL;
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BN_CTX *ctx=NULL;
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int ok=0;
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if (!group)
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{
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GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,GOST_R_KEY_IS_NOT_INITIALIZED);
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return 0;
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}
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ctx=BN_CTX_new();
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BN_CTX_start(ctx);
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if (!(priv_key=EC_KEY_get0_private_key(ec)))
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{
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GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,ERR_R_EC_LIB);
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goto err;
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}
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pub_key = EC_POINT_new(group);
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if (!EC_POINT_mul(group,pub_key,priv_key,NULL,NULL,ctx))
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{
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GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,ERR_R_EC_LIB);
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goto err;
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}
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if (!EC_KEY_set_public_key(ec,pub_key))
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{
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GOSTerr(GOST_F_GOST2001_COMPUTE_PUBLIC,ERR_R_EC_LIB);
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goto err;
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}
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ok = 256;
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err:
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BN_CTX_end(ctx);
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EC_POINT_free(pub_key);
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BN_CTX_free(ctx);
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return ok;
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}
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/*
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*
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* Generates GOST R 34.10-2001 keypair
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*
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*
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*/
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int gost2001_keygen(EC_KEY *ec)
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{
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BIGNUM *order = BN_new(),*d=BN_new();
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const EC_GROUP *group = EC_KEY_get0_group(ec);
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EC_GROUP_get_order(group,order,NULL);
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do
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{
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if (!BN_rand_range(d,order))
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{
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GOSTerr(GOST_F_GOST2001_KEYGEN,GOST_R_RANDOM_NUMBER_GENERATOR_FAILED);
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BN_free(d);
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BN_free(order);
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return 0;
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}
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}
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while (BN_is_zero(d));
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EC_KEY_set_private_key(ec,d);
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BN_free(d);
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BN_free(order);
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return gost2001_compute_public(ec);
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}
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