public function GOST_verifies($hash, Signature $signature)
{
if (extension_loaded('gmp') && USE_EXT == 'GMP') {
$G = $this->generator;
//P
$n = $this->generator->getOrder();
//q
$point = $this->point;
//Q
$r = $signature->getR();
$s = $signature->getS();
if (gmp_cmp($r, 1) < 0 || gmp_cmp($r, gmp_sub($n, 1)) > 0) {
return false;
}
if (gmp_cmp($s, 1) < 0 || gmp_cmp($s, gmp_sub($n, 1)) > 0) {
return false;
}
//step 3 GOST
$e = gmp_Utils::gmp_mod2($hash, $n);
if (gmp_cmp($e, '0') === 0) {
$e = gmp_init('1');
}
// step 4 GOST
$v = gmp_strval(gmp_invert($e, $n));
// step 5 GOST
$z1 = gmp_Utils::gmp_mod2(gmp_mul($s, $v), $n);
$z2 = gmp_Utils::gmp_mod2(gmp_mul(gmp_neg($r), $v), $n);
// step 6 GOST
$C = Point::add(Point::mul($z1, $G), Point::mul($z2, $point));
$R = gmp_Utils::gmp_mod2($C->getX(), $n);
if (0) {
echo "n - " . $n . "\n";
echo "h - " . $hash . "\n";
echo "e - " . gmp_Utils::gmp_dechex($e) . "\n";
echo "v - " . gmp_Utils::gmp_dechex($v) . "\n";
echo "r - " . $r . "\n";
echo "s - " . $s . "\n";
echo "z1 - " . gmp_Utils::gmp_dechex($z1) . "\nz2 - " . gmp_Utils::gmp_dechex($z2) . "\n";
echo "Q - " . $point . "\nG - " . $G . "\n";
echo "C - " . $C . "\nR - " . $R . "\n";
}
if (gmp_cmp($R, $r) == 0) {
return true;
} else {
return false;
}
} else {
throw new ErrorException("Please install GMP");
}
}
function privkey2pubkey($ECDSA, $secp256k1_G)
{
// this is function that needs the phpecc stuff - rewrite when binary module available
$privKey = gmp_Utils::gmp_hexdec($ECDSA);
$pubKey = new PublicKey($secp256k1_G, Point::mul($privKey, $secp256k1_G));
$xcoord = strtoupper(gmp_Utils::gmp_dechex($pubKey->getPoint()->getX()));
$xcoord = str_pad($xcoord, 64, '0', STR_PAD_LEFT);
$ycoord = strtoupper(gmp_Utils::gmp_dechex($pubKey->getPoint()->getY()));
$ycoord = str_pad($ycoord, 64, '0', STR_PAD_LEFT);
return '04' . $xcoord . $ycoord;
}
