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;
55 dh->g = BN_dup(pubk->pkey.dsa->g);
56 dh->p = BN_dup(pubk->pkey.dsa->p);
57 dh->priv_key = BN_dup(priv_key);
58 ret=compute_pair_key_le(dh_key,((DSA *)(EVP_PKEY_get0(pubk)))->pub_key,dh) ;
61 init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet);
62 start_hash(&hash_ctx);
63 hash_block(&hash_ctx,dh_key,128);
64 finish_hash(&hash_ctx,shared_key);
65 done_gost_hash_ctx(&hash_ctx);
69 /* EVP_PKEY_METHOD callback derive. Implements VKO R 34.10-94 */
71 int pkey_gost94_derive(EVP_PKEY_CTX *ctx,unsigned char *key,size_t *keylen)
73 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_peerkey(ctx);
74 EVP_PKEY *mykey = EVP_PKEY_CTX_get0_pkey(ctx);
76 if (key == NULL) return 1;
78 return make_cp_exchange_key(gost_get0_priv_key(mykey), pubk, key);
81 /* EVP_PKEY_METHOD callback encrypt for
82 * GOST R 34.10-94 cryptopro modification
86 int pkey_GOST94cp_encrypt(EVP_PKEY_CTX *ctx, unsigned char *out, size_t *outlen, const unsigned char* key, size_t key_len )
88 GOST_KEY_TRANSPORT *gkt=NULL;
89 unsigned char shared_key[32], ukm[8],crypted_key[44];
90 const struct gost_cipher_info *param=get_encryption_params(NULL);
91 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(ctx);
92 struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(ctx);
95 int key_is_ephemeral=1;
96 EVP_PKEY *mykey = EVP_PKEY_CTX_get0_peerkey(ctx);
98 /* Do not use vizir cipher parameters with cryptopro */
99 if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) && param == gost_cipher_list)
101 param= gost_cipher_list+1;
106 /* If key already set, it is not ephemeral */
108 if (!gost_get0_priv_key(mykey))
110 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
111 GOST_R_NO_PRIVATE_PART_OF_NON_EPHEMERAL_KEYPAIR);
117 /* Otherwise generate ephemeral key */
118 key_is_ephemeral = 1;
121 mykey = EVP_PKEY_new();
122 EVP_PKEY_assign(mykey, EVP_PKEY_base_id(pubk),DSA_new());
123 EVP_PKEY_copy_parameters(mykey,pubk);
124 if (!gost_sign_keygen(EVP_PKEY_get0(mykey)))
131 make_cp_exchange_key(gost_get0_priv_key(mykey),pubk,shared_key);
132 if (data->shared_ukm)
134 memcpy(ukm,data->shared_ukm,8);
138 if (RAND_bytes(ukm,8)<=0)
140 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
141 GOST_R_RANDOM_GENERATOR_FAILURE);
147 gost_init(&cctx,param->sblock);
148 keyWrapCryptoPro(&cctx,shared_key,ukm,key,crypted_key);
150 gkt = GOST_KEY_TRANSPORT_new();
155 if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,
160 if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4))
164 if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32))
168 if (key_is_ephemeral) {
169 if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,out?mykey:pubk))
171 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
174 if (out) EVP_PKEY_free(mykey);
176 ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
177 gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid);
178 *outlen = i2d_GOST_KEY_TRANSPORT(gkt,out?&out:NULL);
181 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,GOST_R_ERROR_PACKING_KEY_TRANSPORT_INFO);
184 GOST_KEY_TRANSPORT_free(gkt);
187 if (key_is_ephemeral) {
188 EVP_PKEY_free(mykey);
190 GOSTerr(GOST_F_PKEY_GOST94CP_ENCRYPT,
191 GOST_R_MALLOC_FAILURE);
193 GOST_KEY_TRANSPORT_free(gkt);
198 /* EVP_PLEY_METHOD callback decrypt for
199 * GOST R 34.10-94 cryptopro modification
201 int pkey_GOST94cp_decrypt(EVP_PKEY_CTX *ctx, unsigned char *key, size_t *key_len,const unsigned char *in, size_t in_len) {
202 const unsigned char *p = in;
203 GOST_KEY_TRANSPORT *gkt = NULL;
204 unsigned char wrappedKey[44];
205 unsigned char sharedKey[32];
207 const struct gost_cipher_info *param=NULL;
208 EVP_PKEY *eph_key=NULL;
209 EVP_PKEY *priv= EVP_PKEY_CTX_get0_pkey(ctx);
217 gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
221 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
224 eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
225 /* No ephemeral key in the structure. Check peer key in the context
228 eph_key = EVP_PKEY_CTX_get0_peerkey(ctx);
230 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
234 /* Increment reference count of peer key */
235 CRYPTO_add(&(eph_key->references),1 ,CRYPTO_LOCK_EVP_PKEY);
239 param = get_encryption_params(gkt->key_agreement_info->cipher);
240 gost_init(&cctx,param->sblock);
241 OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
242 memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
243 OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
244 memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
245 OPENSSL_assert(gkt->key_info->imit->length==4);
246 memcpy(wrappedKey+40,gkt->key_info->imit->data,4);
247 make_cp_exchange_key(gost_get0_priv_key(priv),eph_key,sharedKey);
248 if (!keyUnwrapCryptoPro(&cctx,sharedKey,wrappedKey,key))
250 GOSTerr(GOST_F_PKEY_GOST94CP_DECRYPT,
251 GOST_R_ERROR_COMPUTING_SHARED_KEY);
255 EVP_PKEY_free(eph_key);
256 GOST_KEY_TRANSPORT_free(gkt);
259 EVP_PKEY_free(eph_key);
260 GOST_KEY_TRANSPORT_free(gkt);