1 /**********************************************************************
3 * Copyright (c) 2005-2006 Cryptocom LTD *
4 * This file is distributed under the same license as OpenSSL *
6 * Implements generation and parsing of GOST_KEY_TRANSPORT for *
7 * GOST R 34.10-94 algorithms *
9 * Requires OpenSSL 0.9.9 for compilation *
10 **********************************************************************/
12 #include <openssl/dh.h>
13 #include <openssl/rand.h>
14 #include <openssl/evp.h>
15 #include <openssl/objects.h>
19 #include "e_gost_err.h"
20 #include "gost_keywrap.h"
22 /* Common functions for both 94 and 2001 key exchange schemes */
23 /* Implementation of the Diffi-Hellman key agreement scheme based on
26 /* Computes Diffie-Hellman key and stores it into buffer in
27 * little-endian byte order as expected by both versions of GOST 94
30 static int compute_pair_key_le(unsigned char *pair_key,BIGNUM *pub_key,DH *dh)
32 unsigned char be_key[128];
34 key_size=DH_compute_key(be_key,pub_key,dh);
35 if (!key_size) return 0;
36 memset(pair_key,0,128);
37 for (i=0;i<key_size;i++)
39 pair_key[i]=be_key[key_size-1-i];
45 * Computes 256 bit Key exchange key as specified in RFC 4357
47 static int make_cp_exchange_key(BIGNUM *priv_key,EVP_PKEY *pubk, unsigned char *shared_key)
49 unsigned char dh_key [128];
51 gost_hash_ctx hash_ctx;
57 dh->g = BN_dup(pubk->pkey.dsa->g);
58 dh->p = BN_dup(pubk->pkey.dsa->p);
59 dh->priv_key = BN_dup(priv_key);
60 ret=compute_pair_key_le(dh_key,((DSA *)(EVP_PKEY_get0(pubk)))->pub_key,dh) ;
63 init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet);
64 start_hash(&hash_ctx);
65 hash_block(&hash_ctx,dh_key,128);
66 finish_hash(&hash_ctx,shared_key);
67 done_gost_hash_ctx(&hash_ctx);
71 /* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */
73 int pkey_gost94_derive(EVP_PKEY_CTX *ctx,unsigned char *key,size_t *keylen)
75 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx);
76 EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx);
78 if (key == NULL) return 1;
80 return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key);
83 /* EVP_PKEY_METHOD callback encrypt for
84 * GOST R 34.10-94 cryptopro modification
88 int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char* key, size_t key_len )
90 GOST_KEY_TRANSPORT *gkt=NULL;
91 unsigned char shared_key[32], ukm[8],crypted_key[44];
92 const struct gost_cipher_info *param=get_encryption_params(NULL);
93 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx);
94 struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
97 int key_is_ephemeral=1;
98 EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx);
100 /* Do not use vizir cipher parameters with cryptopro */
101 if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) && param == gost_cipher_list)
103 param= gost_cipher_list+1;
108 /* If key already set, it is not ephemeral */
110 if (!gost_get0_priv_key(mykey))
112 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
113 GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR);
119 /* Otherwise generate ephemeral key */
120 key_is_ephemeral = 1;
123 mykey = EVP_PKEY_new();
124 EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk),DSA_new());
125 EVP_PKEY_copy_parameters(mykey,pubk);
126 if (!gost_sign_keygen(EVP_PKEY_get0(mykey)))
133 make_cp_exchange_key(gost_get0_priv_key(mykey),pubk,shared_key);
134 if (data->shared_ukm)
136 memcpy(ukm,data->shared_ukm,8);
140 if (RAND_bytes(ukm,8)<=0)
142 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
143 GOST_R_RANDOM_GENERATOR_FAILURE);
149 gost_init(&cctx,param->sblock);
150 keyWrapCryptoPro(&cctx,shared_key,ukm,key,crypted_key);
152 gkt = GOST_KEY_TRANSPORT_new();
157 if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,
162 if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4))
166 if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32))
170 if (key_is_ephemeral) {
171 if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,out?mykey:pubk))
173 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
176 if (out) EVP_PKEY_free(mykey);
178 ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
179 gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid);
180 *outlen = i2d_GOST_KEY_TRANSPORT(gkt,out?&out:NULL);
183 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO);
186 GOST_KEY_TRANSPORT_free(gkt);
189 if (key_is_ephemeral) {
190 EVP_PKEY_free(mykey);
192 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
193 GOST_R_MALLOC_FAILURE);
195 GOST_KEY_TRANSPORT_free(gkt);
200 /* EVP_PLEY_METHOD callback decrypt for
201 * GOST R 34.10-94 cryptopro modification
203 int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *key_len,const unsigned char *in, size_t in_len) {
204 const unsigned char *p = in;
205 GOST_KEY_TRANSPORT *gkt = NULL;
206 unsigned char wrappedKey[44];
207 unsigned char sharedKey[32];
209 const struct gost_cipher_info *param=NULL;
210 EVP_PKEY *eph_key=NULL;
211 EVP_PKEY *priv= EVP_PKEY_CTX_get0_pkey(ctx);
219 gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
223 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
226 eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
227 /* No ephemeral key in the structure. Check peer key in the context
230 eph_key = EVP_PKEY_CTX_get0_peerkey(ctx);
232 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
236 /* Increment reference count of peer key */
237 CRYPTO_add(&(eph_key->references),1 ,CRYPTO_LOCK_EVP_PKEY);
241 param = get_encryption_params(gkt->key_agreement_info->cipher);
242 gost_init(&cctx,param->sblock);
243 OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
244 memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
245 OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
246 memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
247 OPENSSL_assert(gkt->key_info->imit->length==4);
248 memcpy(wrappedKey+40,gkt->key_info->imit->data,4);
249 make_cp_exchange_key(gost_get0_priv_key(priv),eph_key,sharedKey);
250 if (!keyUnwrapCryptoPro(&cctx,sharedKey,wrappedKey,key))
252 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
253 GOST_R_ERROR_COMPUTING_SHARED_KEY);
257 EVP_PKEY_free(eph_key);
258 GOST_KEY_TRANSPORT_free(gkt);
261 EVP_PKEY_free(eph_key);
262 GOST_KEY_TRANSPORT_free(gkt);