--- /dev/null
+/**********************************************************************
+ * 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);
+ newsig = NULL;
+ 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);
+ newsig = NULL;
+ 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);
+ newsig = NULL;
+ 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);
+ }
+
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