int pkey_GOST01cp_decrypt(EVP_PKEY_CTX *pctx, unsigned char *key, size_t * key_len, const unsigned char *in, size_t in_len)
	{
	const unsigned char *p = in;
	EVP_PKEY *priv = EVP_PKEY_CTX_get0_pkey(pctx);
	GOST_KEY_TRANSPORT *gkt = NULL;
	int ret=0;	
	unsigned char wrappedKey[44];
	unsigned char sharedKey[32];
	gost_ctx ctx;
	const struct gost_cipher_info *param=NULL;
	EVP_PKEY *eph_key=NULL, *peerkey=NULL;

	if (!key)
		{
		*key_len = 32;
		return 1;
		}	
	gkt = d2i_GOST_KEY_TRANSPORT(NULL,(const unsigned char **)&p,
		in_len);
	if (!gkt)
		{
		GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,GOST_R_ERROR_PARSING_KEY_TRANSPORT_INFO);
		return -1;
		}	

	/* If key transport structure contains public key, use it */
	eph_key = X509_PUBKEY_get(gkt->key_agreement_info->ephem_key);
	if (eph_key)
		{
		if (EVP_PKEY_derive_set_peer(pctx, eph_key) <= 0)
			{
			GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,
				GOST_R_INCOMPATIBLE_PEER_KEY);
			goto err;
			}
		}
	else
		{
		/* Set control "public key from client certificate used" */
		if (EVP_PKEY_CTX_ctrl(pctx, -1, -1, EVP_PKEY_CTRL_PEER_KEY, 3, NULL) <= 0)
			{
			GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,
				GOST_R_CTRL_CALL_FAILED);
			goto err;
			}
		}
	peerkey = EVP_PKEY_CTX_get0_peerkey(pctx);
	if (!peerkey)
		{
		GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,
			GOST_R_NO_PEER_KEY);
		goto err;
		}
		
	param = get_encryption_params(gkt->key_agreement_info->cipher);
	gost_init(&ctx,param->sblock);	
	OPENSSL_assert(gkt->key_agreement_info->eph_iv->length==8);
	memcpy(wrappedKey,gkt->key_agreement_info->eph_iv->data,8);
	OPENSSL_assert(gkt->key_info->encrypted_key->length==32);
	memcpy(wrappedKey+8,gkt->key_info->encrypted_key->data,32);
	OPENSSL_assert(gkt->key_info->imit->length==4);
	memcpy(wrappedKey+40,gkt->key_info->imit->data,4);	
	VKO_compute_key(sharedKey,32,EC_KEY_get0_public_key(EVP_PKEY_get0(peerkey)),
		EVP_PKEY_get0(priv),wrappedKey);
	if (!keyUnwrapCryptoPro(&ctx,sharedKey,wrappedKey,key))
		{
		GOSTerr(GOST_F_PKEY_GOST01CP_DECRYPT,
			GOST_R_ERROR_COMPUTING_SHARED_KEY);
		goto err;
		}	
				
	ret=1;
err:	
	if (eph_key) EVP_PKEY_free(eph_key);
	if (gkt) GOST_KEY_TRANSPORT_free(gkt);
	return ret;
	}