1 /**********************************************************************
3 * Copyright (c) 2005-2006 Cryptocom LTD *
4 * This file is distributed under the same license as OpenSSL *
6 * VK0 34.10-2001 key exchange and GOST R 34.10-2001 *
7 * based PKCS7/SMIME support *
8 * Requires OpenSSL 0.9.9 for compilation *
9 **********************************************************************/
10 #include <openssl/evp.h>
11 #include <openssl/rand.h>
13 #include <openssl/objects.h>
16 #include "e_gost_err.h"
17 #include "gost_keywrap.h"
19 #include "gost2001_keyx.h"
21 /* Transform ECDH shared key into little endian as required by Cryptocom
23 static void *make_key_le(const void *in, size_t inlen, void *out, size_t *outlen)
25 const char* inbuf= in;
34 outbuf[inlen-1-i]=inbuf[i];
40 /* Create gost 2001 ephemeral key with same parameters as peer key */
41 static EC_KEY *make_ec_ephemeral_key(EC_KEY *peer_key,BIGNUM *seckey)
43 EC_KEY *out = EC_KEY_new();
44 EC_KEY_copy(out,peer_key);
45 EC_KEY_set_private_key(out,seckey);
46 gost2001_compute_public(out);
49 /* Packs GOST elliptic curve key into EVP_PKEY setting same parameters
52 static EVP_PKEY *ec_ephemeral_key_to_EVP(EVP_PKEY *pubk,int type,EC_KEY *ephemeral)
55 newkey = EVP_PKEY_new();
56 EVP_PKEY_assign(newkey,type,ephemeral);
61 * EVP_PKEY_METHOD callback encrypt
62 * Implementation of GOST2001 key transport, cryptocom variation
65 int pkey_GOST01cc_encrypt (EVP_PKEY_CTX *pctx,unsigned char *out,
66 size_t *out_len, const unsigned char *key,size_t key_len)
68 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(pctx);
69 struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx);
70 GOST_KEY_TRANSPORT *gkt = NULL;
72 const struct gost_cipher_info *cipher_info;
74 EC_KEY *ephemeral=NULL;
75 const EC_POINT *pub_key_point=NULL;
76 unsigned char shared_key[32],encrypted_key[32],hmac[4],
77 iv[8]={0,0,0,0,0,0,0,0};
78 ephemeral = make_ec_ephemeral_key(EVP_PKEY_get0(pubk), gost_get_priv_key(data->eph_seckey));
79 if (!ephemeral) goto err;
80 /* compute shared key */
81 pub_key_point=EC_KEY_get0_public_key(EVP_PKEY_get0(pubk));
82 if (!ECDH_compute_key(shared_key,32,pub_key_point,ephemeral,make_key_le))
84 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_COMPUTING_SHARED_KEY);
87 /* encrypt session key */
88 cipher_info = get_encryption_params(NULL);
89 gost_init(&ctx, cipher_info->sblock);
90 gost_key(&ctx,shared_key);
91 encrypt_cryptocom_key(key,key_len,encrypted_key,&ctx);
92 /* compute hmac of session key */
93 if (!gost_mac(&ctx,32,key,32,hmac))
95 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_COMPUTING_MAC);
98 gkt = GOST_KEY_TRANSPORT_new();
101 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_NO_MEMORY);
104 /* Store IV which is always zero in our case */
105 if (!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,iv,8))
107 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_STORING_IV);
110 if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,hmac,4))
112 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_STORING_MAC);
115 if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,encrypted_key,32))
117 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_ERROR_STORING_ENCRYPTED_KEY);
121 if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,data->eph_seckey))
123 GOSTerr(GOST_F_PKEY_GOST01CC_ENCRYPT,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
126 ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
127 gkt->key_agreement_info->cipher = OBJ_nid2obj(cipher_info->nid);
128 if ((*out_len = i2d_GOST_KEY_TRANSPORT(gkt,&out))>0) ret = 1;
131 if (gkt) GOST_KEY_TRANSPORT_free(gkt);
135 * EVP_PKEY_METHOD callback decrypt
136 * Implementation of GOST2001 key transport, cryptocom variation
138 int pkey_GOST01cc_decrypt (EVP_PKEY_CTX *pctx, unsigned char *key, size_t *key_len, const unsigned char *in, size_t in_len)
140 /* Form DH params from compute shared key */
141 EVP_PKEY *priv=EVP_PKEY_CTX_get0_pkey(pctx);
142 GOST_KEY_TRANSPORT *gkt = NULL;
143 const unsigned char *p=in;
144 unsigned char shared_key[32];
145 unsigned char hmac[4],hmac_comp[4];
148 const struct gost_cipher_info *cipher_info;
150 const EC_POINT *pub_key_point;
158 /* Parse passed octet string and find out public key, iv and HMAC*/
159 gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
163 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
166 eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
167 /* Initialization vector is really ignored here */
168 OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
169 memcpy(iv,gkt->key_agreement_info->eph_iv->data,8);
170 /* HMAC should be computed and checked */
171 OPENSSL_assert(gkt->key_info->imit->length==4);
172 memcpy(hmac,gkt->key_info->imit->data,4);
173 /* Compute shared key */
174 pub_key_point=EC_KEY_get0_public_key(EVP_PKEY_get0(eph_key));
175 i=ECDH_compute_key(shared_key,32,pub_key_point,EVP_PKEY_get0(priv),make_key_le);
176 EVP_PKEY_free(eph_key);
179 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_ERROR_COMPUTING_SHARED_KEY);
180 GOST_KEY_TRANSPORT_free(gkt);
183 /* Decrypt session key */
184 cipher_info = get_encryption_params(gkt->key_agreement_info->cipher);
185 gost_init(&ctx, cipher_info->sblock);
186 gost_key(&ctx,shared_key);
188 if (!decrypt_cryptocom_key(key,*key_len,gkt->key_info->encrypted_key->data,
189 gkt->key_info->encrypted_key->length, &ctx))
191 GOST_KEY_TRANSPORT_free(gkt);
194 GOST_KEY_TRANSPORT_free(gkt);
195 /* check HMAC of session key*/
196 if (!gost_mac(&ctx,32,key,32,hmac_comp))
198 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_ERROR_COMPUTING_MAC);
201 /* HMAC of session key is not correct */
202 if (memcmp(hmac,hmac_comp,4)!=0)
204 GOSTerr(GOST_F_PKEY_GOST01CC_DECRYPT,GOST_R_SESSION_KEY_MAC_DOES_NOT_MATCH);
210 /* Implementation of CryptoPro VKO 34.10-2001 algorithm */
211 static int VKO_compute_key(unsigned char *shared_key,size_t shared_key_size,const EC_POINT *pub_key,EC_KEY *priv_key,const unsigned char *ukm)
213 unsigned char ukm_be[8],databuf[64],hashbuf[64];
214 BIGNUM *UKM=NULL,*p=NULL,*order=NULL,*X=NULL,*Y=NULL;
215 const BIGNUM* key=EC_KEY_get0_private_key(priv_key);
216 EC_POINT *pnt=EC_POINT_new(EC_KEY_get0_group(priv_key));
218 gost_hash_ctx hash_ctx;
219 BN_CTX *ctx = BN_CTX_new();
226 UKM=getbnfrombuf(ukm_be,8);
228 order = BN_CTX_get(ctx);
231 EC_GROUP_get_order(EC_KEY_get0_group(priv_key),order,ctx);
232 BN_mod_mul(p,key,UKM,order,ctx);
233 EC_POINT_mul(EC_KEY_get0_group(priv_key),pnt,NULL,pub_key,p,ctx);
234 EC_POINT_get_affine_coordinates_GFp(EC_KEY_get0_group(priv_key),
236 /*Serialize elliptic curve point same way as we do it when saving
238 store_bignum(Y,databuf,32);
239 store_bignum(X,databuf+32,32);
240 /* And reverse byte order of whole buffer */
243 hashbuf[63-i]=databuf[i];
245 init_gost_hash_ctx(&hash_ctx,&GostR3411_94_CryptoProParamSet);
246 start_hash(&hash_ctx);
247 hash_block(&hash_ctx,hashbuf,64);
248 finish_hash(&hash_ctx,shared_key);
249 done_gost_hash_ctx(&hash_ctx);
257 /* Generates ephemeral key based on pubk algorithm
258 * computes shared key using VKO and returns filled up
259 * GOST_KEY_TRANSPORT structure
261 /* Public, because it would be needed in SSL implementation */
262 GOST_KEY_TRANSPORT *make_rfc4490_keytransport_2001(EVP_PKEY *pubk,BIGNUM *eph_key,
263 const unsigned char *key,size_t keylen, unsigned char *ukm,
267 const struct gost_cipher_info *param=get_encryption_params(NULL);
268 EC_KEY *ephemeral = NULL;
269 GOST_KEY_TRANSPORT *gkt=NULL;
270 const EC_POINT *pub_key_point = EC_KEY_get0_public_key(EVP_PKEY_get0(pubk));
271 unsigned char shared_key[32],crypted_key[44];
273 EVP_PKEY *newkey=NULL;
275 /* Do not use vizir cipher parameters with cryptopro */
276 if (!get_gost_engine_param(GOST_PARAM_CRYPT_PARAMS) && param == gost_cipher_list)
278 param= gost_cipher_list+1;
280 ephemeral = make_ec_ephemeral_key(EVP_PKEY_get0(pubk),eph_key);
281 VKO_compute_key(shared_key,32,pub_key_point,ephemeral,ukm);
282 gost_init(&ctx,param->sblock);
283 keyWrapCryptoPro(&ctx,shared_key,ukm,key,crypted_key);
284 gkt = GOST_KEY_TRANSPORT_new();
289 if(!ASN1_OCTET_STRING_set(gkt->key_agreement_info->eph_iv,
294 if (!ASN1_OCTET_STRING_set(gkt->key_info->imit,crypted_key+40,4))
298 if (!ASN1_OCTET_STRING_set(gkt->key_info->encrypted_key,crypted_key+8,32))
302 newkey = ec_ephemeral_key_to_EVP(pubk,NID_id_GostR3410_2001,ephemeral);
303 if (!X509_PUBKEY_set(&gkt->key_agreement_info->ephem_key,newkey))
305 GOSTerr(GOST_F_MAKE_RFC4490_KEYTRANSPORT_2001,GOST_R_CANNOT_PACK_EPHEMERAL_KEY);
308 ASN1_OBJECT_free(gkt->key_agreement_info->cipher);
309 gkt->key_agreement_info->cipher = OBJ_nid2obj(param->nid);
310 EVP_PKEY_free(newkey);
313 GOSTerr(GOST_F_MAKE_RFC4490_KEYTRANSPORT_2001,
314 GOST_R_MALLOC_FAILURE);
316 GOST_KEY_TRANSPORT_free(gkt);
321 * EVP_PKEY_METHOD callback encrypt
322 * Implementation of GOST2001 key transport, cryptopo variation
325 int pkey_GOST01cp_encrypt (EVP_PKEY_CTX *pctx, unsigned char *out, size_t *out_len, const unsigned char *key,size_t key_len)
327 GOST_KEY_TRANSPORT *gkt=NULL;
328 EVP_PKEY *pubk = EVP_PKEY_CTX_get0_pkey(pctx);
329 struct gost_pmeth_data *data = EVP_PKEY_CTX_get_data(pctx);
330 unsigned char ukm[8];
332 if (RAND_bytes(ukm,8)<=0)
334 GOSTerr(GOST_F_PKEY_GOST01CP_ENCRYPT,
335 GOST_R_RANDOM_GENERATOR_FAILURE);
339 if (!(gkt=make_rfc4490_keytransport_2001(pubk,gost_get_priv_key(data->eph_seckey),key, key_len,ukm,8)))
343 if ((*out_len = i2d_GOST_KEY_TRANSPORT(gkt,&out))>0) ret =1;
344 GOST_KEY_TRANSPORT_free(gkt);
347 GOST_KEY_TRANSPORT_free(gkt);
350 /* Public, because it would be needed in SSL implementation */
351 int decrypt_rfc4490_shared_key_2001(EVP_PKEY *priv,GOST_KEY_TRANSPORT *gkt,
352 unsigned char *key_buf,int key_buf_len)
354 unsigned char wrappedKey[44];
355 unsigned char sharedKey[32];
357 const struct gost_cipher_info *param=NULL;
358 EVP_PKEY *eph_key=NULL;
360 eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
361 param = get_encryption_params(gkt->key_agreement_info->cipher);
362 gost_init(&ctx,param->sblock);
363 OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
364 memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
365 OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
366 memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
367 OPENSSL_assert(gkt->key_info->imit->length==4);
368 memcpy(wrappedKey+40,gkt->key_info->imit->data,4);
369 VKO_compute_key(sharedKey,32,EC_KEY_get0_public_key(EVP_PKEY_get0(eph_key)),
370 EVP_PKEY_get0(priv),wrappedKey);
371 if (!keyUnwrapCryptoPro(&ctx,sharedKey,wrappedKey,key_buf))
373 GOSTerr(GOST_F_PKCS7_GOST94CP_KEY_TRANSPORT_DECRYPT,
374 GOST_R_ERROR_COMPUTING_SHARED_KEY);
378 EVP_PKEY_free(eph_key);
381 EVP_PKEY_free(eph_key);
385 * EVP_PKEY_METHOD callback decrypt
386 * Implementation of GOST2001 key transport, cryptopo variation
388 int pkey_GOST01cp_decrypt (EVP_PKEY_CTX *pctx, unsigned char *key, size_t * key_len, const unsigned char *in, size_t in_len)
390 const unsigned char *p = in;
391 EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx);
392 GOST_KEY_TRANSPORT *gkt = NULL;
400 gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
404 GOSTerr(GOST_F_PKCS7_GOST94CP_KEY_TRANSPORT_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
407 ret = decrypt_rfc4490_shared_key_2001(priv,gkt,key,*key_len);
408 GOST_KEY_TRANSPORT_free(gkt);