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/*****************************************************************************
 OSSLGOSTPublicKey.cpp

 OpenSSL GOST R 34.10-2001 public key class
 *****************************************************************************/

#include "config.h"
#ifdef WITH_GOST
#include "log.h"
#include "OSSLGOSTPublicKey.h"
#include <openssl/x509.h>
#include <string.h>

// the 37 bytes of prefix
const unsigned char gost_prefix[] = {
	0x30, 0x63, 0x30, 0x1c, 0x06, 0x06, 0x2a, 0x85,
	0x03, 0x02, 0x02, 0x13, 0x30, 0x12, 0x06, 0x07,
	0x2a, 0x85, 0x03, 0x02, 0x02, 0x23, 0x01, 0x06,
	0x07, 0x2a, 0x85, 0x03, 0x02, 0x02, 0x1e, 0x01,
	0x03, 0x43, 0x00, 0x04, 0x40
};

// Constructors
OSSLGOSTPublicKey::OSSLGOSTPublicKey()
{
	pkey = EVP_PKEY_new();
}

OSSLGOSTPublicKey::OSSLGOSTPublicKey(const EVP_PKEY* inPKEY)
{
	OSSLGOSTPublicKey();

	setFromOSSL(inPKEY);
}

// Destructor
OSSLGOSTPublicKey::~OSSLGOSTPublicKey()
{
	EVP_PKEY_free(pkey);
}

// The type
/*static*/ const char* OSSLGOSTPublicKey::type = "OpenSSL GOST Public Key";

// Get the output length
unsigned long OSSLGOSTPublicKey::getOutputLength() const
{
	return getQ().size();
}

// Set from OpenSSL representation
void OSSLGOSTPublicKey::setFromOSSL(const EVP_PKEY* pkey)
{
	ByteString der;
	int len = i2d_PUBKEY((EVP_PKEY*) pkey, NULL);
	if (len != 37 + 64)
	{
		ERROR_MSG("bad GOST public key encoding length %d", len);
		return;
	}
	der.resize(len);
	unsigned char *p = &der[0];
	i2d_PUBKEY((EVP_PKEY*) pkey, &p);
	// can check: der is prefix + 64 bytes
	setQ(der.substr(37));

	ByteString inEC;
	const EC_KEY* eckey = (const EC_KEY*) EVP_PKEY_get0((EVP_PKEY*) pkey);
	int nid = EC_GROUP_get_curve_name(EC_KEY_get0_group(eckey));
	inEC.resize(i2d_ASN1_OBJECT(OBJ_nid2obj(nid), NULL));
	p = &inEC[0];
	i2d_ASN1_OBJECT(OBJ_nid2obj(nid), &p);
	setEC(inEC);
}

// Check if the key is of the given type
bool OSSLGOSTPublicKey::isOfType(const char* inType)
{
	return !strcmp(type, inType);
}

// Setters for the GOST public key components
void OSSLGOSTPublicKey::setEC(const ByteString& inEC)
{
        GOSTPublicKey::setEC(inEC);
}

void OSSLGOSTPublicKey::setQ(const ByteString& inQ)
{
	GOSTPublicKey::setQ(inQ);

	if (inQ.size() != 64)
	{
		ERROR_MSG("bad GOST public key size %zu", q.size());
		return;
	}

	ByteString der;
	der.resize(37 + 64);
	memcpy(&der[0], gost_prefix, 37);
	memcpy(&der[37], inQ.const_byte_str(), 64);
	const unsigned char *p = &der[0];
	if (d2i_PUBKEY(&pkey, &p, (long) der.size()) == NULL)
		ERROR_MSG("d2i_PUBKEY failed");
}

// Serialisation
ByteString OSSLGOSTPublicKey::serialise() const
{
	return ec.serialise() +
	       q.serialise();
}

bool OSSLGOSTPublicKey::deserialise(ByteString& serialised)
{
	ByteString dEC = ByteString::chainDeserialise(serialised);
	ByteString dQ = ByteString::chainDeserialise(serialised);

	if ((dEC.size() == 0) ||
	    (dQ.size() == 0))
	{
		return false;
	}

	setEC(dEC);
	setQ(dQ);

	return true;
}

// Retrieve the OpenSSL representation of the key
EVP_PKEY* OSSLGOSTPublicKey::getOSSLKey()
{
	return pkey;
}
#endif