+++ /dev/null
-/**********************************************************************
- * gost_sign.c *
- * Copyright (c) 2005-2006 Cryptocom LTD *
- * This file is distributed under the same license as OpenSSL *
- * *
- * Implementation of GOST R 34.10-94 signature algorithm *
- * for OpenSSL *
- * Requires OpenSSL 0.9.9 for compilation *
- **********************************************************************/
-#include <string.h>
-#include <openssl/rand.h>
-#include <openssl/bn.h>
-#include <openssl/dsa.h>
-#include <openssl/evp.h>
-
-#include "gost_params.h"
-#include "gost_lcl.h"
-#include "e_gost_err.h"
-
-#ifdef DEBUG_SIGN
-void dump_signature(const char *message,const unsigned char *buffer,size_t len)
- {
- size_t i;
- fprintf(stderr,"signature %s Length=%d",message,len);
- for (i=0; i<len; i++)
- {
- if (i% 16 ==0) fputc('\n',stderr);
- fprintf (stderr," %02x",buffer[i]);
- }
- fprintf(stderr,"\nEnd of signature\n");
- }
-
-void dump_dsa_sig(const char *message, DSA_SIG *sig)
- {
- fprintf(stderr,"%s\nR=",message);
- BN_print_fp(stderr,sig->r);
- fprintf(stderr,"\nS=");
- BN_print_fp(stderr,sig->s);
- fprintf(stderr,"\n");
- }
-
-#else
-
-#define dump_signature(a,b,c)
-#define dump_dsa_sig(a,b)
-#endif
-
-/*
- * Computes signature and returns it as DSA_SIG structure
- */
-DSA_SIG *gost_do_sign(const unsigned char *dgst,int dlen, DSA *dsa)
- {
- BIGNUM *k=NULL,*tmp=NULL,*tmp2=NULL;
- DSA_SIG *newsig = DSA_SIG_new();
- BIGNUM *md = hashsum2bn(dgst);
- /* check if H(M) mod q is zero */
- BN_CTX *ctx=BN_CTX_new();
- BN_CTX_start(ctx);
- if (!newsig)
- {
- GOSTerr(GOST_F_GOST_DO_SIGN,GOST_R_NO_MEMORY);
- goto err;
- }
- tmp=BN_CTX_get(ctx);
- k = BN_CTX_get(ctx);
- tmp2 = BN_CTX_get(ctx);
- BN_mod(tmp,md,dsa->q,ctx);
- if (BN_is_zero(tmp))
- {
- BN_one(md);
- }
- do
- {
- do
- {
- /*Generate random number k less than q*/
- BN_rand_range(k,dsa->q);
- /* generate r = (a^x mod p) mod q */
- BN_mod_exp(tmp,dsa->g, k, dsa->p,ctx);
- if (!(newsig->r)) newsig->r=BN_new();
- BN_mod(newsig->r,tmp,dsa->q,ctx);
- }
- while (BN_is_zero(newsig->r));
- /* generate s = (xr + k(Hm)) mod q */
- BN_mod_mul(tmp,dsa->priv_key,newsig->r,dsa->q,ctx);
- BN_mod_mul(tmp2,k,md,dsa->q,ctx);
- if (!newsig->s) newsig->s=BN_new();
- BN_mod_add(newsig->s,tmp,tmp2,dsa->q,ctx);
- }
- while (BN_is_zero(newsig->s));
- err:
- BN_free(md);
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- return newsig;
- }
-
-
-/*
- * Packs signature according to Cryptocom rules
- * and frees up DSA_SIG structure
- */
-/*
-int pack_sign_cc(DSA_SIG *s,int order,unsigned char *sig, size_t *siglen)
- {
- *siglen = 2*order;
- memset(sig,0,*siglen);
- store_bignum(s->r, sig,order);
- store_bignum(s->s, sig + order,order);
- dump_signature("serialized",sig,*siglen);
- DSA_SIG_free(s);
- return 1;
- }
-*/
-/*
- * Packs signature according to Cryptopro rules
- * and frees up DSA_SIG structure
- */
-int pack_sign_cp(DSA_SIG *s,int order,unsigned char *sig, size_t *siglen)
- {
- *siglen = 2*order;
- memset(sig,0,*siglen);
- store_bignum(s->s, sig, order);
- store_bignum(s->r, sig+order,order);
- dump_signature("serialized",sig,*siglen);
- DSA_SIG_free(s);
- return 1;
- }
-
-/*
- * Verifies signature passed as DSA_SIG structure
- *
- */
-
-int gost_do_verify(const unsigned char *dgst, int dgst_len,
- DSA_SIG *sig, DSA *dsa)
- {
- BIGNUM *md, *tmp=NULL;
- BIGNUM *q2=NULL;
- BIGNUM *u=NULL,*v=NULL,*z1=NULL,*z2=NULL;
- BIGNUM *tmp2=NULL,*tmp3=NULL;
- int ok;
- BN_CTX *ctx = BN_CTX_new();
-
- BN_CTX_start(ctx);
- if (BN_cmp(sig->s,dsa->q)>=1||
- BN_cmp(sig->r,dsa->q)>=1)
- {
- GOSTerr(GOST_F_GOST_DO_VERIFY,GOST_R_SIGNATURE_PARTS_GREATER_THAN_Q);
- return 0;
- }
- md=hashsum2bn(dgst);
-
- tmp=BN_CTX_get(ctx);
- v=BN_CTX_get(ctx);
- q2=BN_CTX_get(ctx);
- z1=BN_CTX_get(ctx);
- z2=BN_CTX_get(ctx);
- tmp2=BN_CTX_get(ctx);
- tmp3=BN_CTX_get(ctx);
- u = BN_CTX_get(ctx);
-
- BN_mod(tmp,md,dsa->q,ctx);
- if (BN_is_zero(tmp))
- {
- BN_one(md);
- }
- BN_copy(q2,dsa->q);
- BN_sub_word(q2,2);
- BN_mod_exp(v,md,q2,dsa->q,ctx);
- BN_mod_mul(z1,sig->s,v,dsa->q,ctx);
- BN_sub(tmp,dsa->q,sig->r);
- BN_mod_mul(z2,tmp,v,dsa->p,ctx);
- BN_mod_exp(tmp,dsa->g,z1,dsa->p,ctx);
- BN_mod_exp(tmp2,dsa->pub_key,z2,dsa->p,ctx);
- BN_mod_mul(tmp3,tmp,tmp2,dsa->p,ctx);
- BN_mod(u,tmp3,dsa->q,ctx);
- ok= BN_cmp(u,sig->r);
-
- BN_free(md);
- BN_CTX_end(ctx);
- BN_CTX_free(ctx);
- if (ok!=0)
- {
- GOSTerr(GOST_F_GOST_DO_VERIFY,GOST_R_SIGNATURE_MISMATCH);
- }
- return (ok==0);
- }
-
-/*
- * Computes public keys for GOST R 34.10-94 algorithm
- *
- */
-int gost94_compute_public(DSA *dsa)
- {
- /* Now fill algorithm parameters with correct values */
- BN_CTX *ctx = BN_CTX_new();
- if (!dsa->g)
- {
- GOSTerr(GOST_F_GOST94_COMPUTE_PUBLIC,GOST_R_KEY_IS_NOT_INITALIZED);
- return 0;
- }
- /* Compute public key y = a^x mod p */
- dsa->pub_key=BN_new();
- BN_mod_exp(dsa->pub_key, dsa->g,dsa->priv_key,dsa->p,ctx);
- BN_CTX_free(ctx);
- return 1;
- }
-
-/*
- * Fill GOST 94 params, searching them in R3410_paramset array
- * by nid of paramset
- *
- */
-int fill_GOST94_params(DSA *dsa,int nid)
- {
- R3410_params *params=R3410_paramset;
- while (params->nid!=NID_undef && params->nid !=nid) params++;
- if (params->nid == NID_undef)
- {
- GOSTerr(GOST_F_FILL_GOST94_PARAMS,GOST_R_UNSUPPORTED_PARAMETER_SET);
- return 0;
- }
-#define dump_signature(a,b,c)
- if (dsa->p) { BN_free(dsa->p); }
- dsa->p=NULL;
- BN_dec2bn(&(dsa->p),params->p);
- if (dsa->q) { BN_free(dsa->q); }
- dsa->q=NULL;
- BN_dec2bn(&(dsa->q),params->q);
- if (dsa->g) { BN_free(dsa->g); }
- dsa->g=NULL;
- BN_dec2bn(&(dsa->g),params->a);
- return 1;
- }
-
-/*
- * Generate GOST R 34.10-94 keypair
- *
- *
- */
-int gost_sign_keygen(DSA *dsa)
- {
- dsa->priv_key = BN_new();
- BN_rand_range(dsa->priv_key,dsa->q);
- return gost94_compute_public( dsa);
- }
-
-/* Unpack signature according to cryptocom rules */
-/*
-DSA_SIG *unpack_cc_signature(const unsigned char *sig,size_t siglen)
- {
- DSA_SIG *s;
- s = DSA_SIG_new();
- if (s == NULL)
- {
- GOSTerr(GOST_F_UNPACK_CC_SIGNATURE,GOST_R_NO_MEMORY);
- return(NULL);
- }
- s->r = getbnfrombuf(sig, siglen/2);
- s->s = getbnfrombuf(sig + siglen/2, siglen/2);
- return s;
- }
-*/
-/* Unpack signature according to cryptopro rules */
-DSA_SIG *unpack_cp_signature(const unsigned char *sig,size_t siglen)
- {
- DSA_SIG *s;
-
- s = DSA_SIG_new();
- if (s == NULL)
- {
- GOSTerr(GOST_F_UNPACK_CP_SIGNATURE,GOST_R_NO_MEMORY);
- return NULL;
- }
- s->s = getbnfrombuf(sig , siglen/2);
- s->r = getbnfrombuf(sig + siglen/2, siglen/2);
- return s;
- }
-
-/* Convert little-endian byte array into bignum */
-BIGNUM *hashsum2bn(const unsigned char *dgst)
- {
- unsigned char buf[32];
- int i;
- for (i=0;i<32;i++)
- {
- buf[31-i]=dgst[i];
- }
- return getbnfrombuf(buf,32);
- }
-
-/* Convert byte buffer to bignum, skipping leading zeros*/
-BIGNUM *getbnfrombuf(const unsigned char *buf,size_t len)
- {
- while (*buf==0&&len>0)
- {
- buf++; len--;
- }
- if (len)
- {
- return BN_bin2bn(buf,len,NULL);
- }
- else
- {
- BIGNUM *b=BN_new();
- BN_zero(b);
- return b;
- }
- }
-
-/* Pack bignum into byte buffer of given size, filling all leading bytes
- * by zeros */
-int store_bignum(BIGNUM *bn, unsigned char *buf,int len)
- {
- int bytes = BN_num_bytes(bn);
- if (bytes>len) return 0;
- memset(buf,0,len);
- BN_bn2bin(bn,buf+len-bytes);
- return 1;
- }
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