function recoverPubKey($r, $s, $e, $recoveryFlags, $G)
{
$isYEven = ($recoveryFlags & 1) != 0;
$isSecondKey = ($recoveryFlags & 2) != 0;
$curve = $G->getCurve();
$signature = new Signature($r, $s);
// Precalculate (p + 1) / 4 where p is the field order
static $p_over_four;
// XXX just assuming only one curve/prime will be used
if (!$p_over_four) {
$p_over_four = gmp_div(gmp_add($curve->getPrime(), 1), 4);
}
// 1.1 Compute x
if (!$isSecondKey) {
$x = $r;
} else {
$x = gmp_add($r, $G->getOrder());
}
// 1.3 Convert x to point
$alpha = gmp_mod(gmp_add(gmp_add(gmp_pow($x, 3), gmp_mul($curve->getA(), $x)), $curve->getB()), $curve->getPrime());
$beta = NumberTheory::modular_exp($alpha, $p_over_four, $curve->getPrime());
// If beta is even, but y isn't or vice versa, then convert it,
// otherwise we're done and y == beta.
if (isBignumEven($beta) == $isYEven) {
$y = gmp_sub($curve->getPrime(), $beta);
} else {
$y = $beta;
}
// 1.4 Check that nR is at infinity (implicitly done in construtor)
$R = new Point($curve, $x, $y, $G->getOrder());
$point_negate = function ($p) {
return new Point($p->curve, $p->x, gmp_neg($p->y), $p->order);
};
// 1.6.1 Compute a candidate public key Q = r^-1 (sR - eG)
$rInv = NumberTheory::inverse_mod($r, $G->getOrder());
$eGNeg = $point_negate(Point::mul($e, $G));
$Q = Point::mul($rInv, Point::add(Point::mul($s, $R), $eGNeg));
// 1.6.2 Test Q as a public key
$Qk = new PublicKey($G, $Q);
if ($Qk->verifies($e, $signature)) {
return $Qk;
}
return false;
}
public function sign($hash, $random_k)
{
if (extension_loaded('gmp') && USE_EXT == 'GMP') {
$G = $this->public_key->getGenerator();
$n = $G->getOrder();
$k = gmp_Utils::gmp_mod2($random_k, $n);
$p1 = Point::mul($k, $G);
$r = $p1->getX();
if (gmp_cmp($r, 0) == 0) {
throw new ErrorException("error: random number R = 0 <br />");
}
$s = gmp_Utils::gmp_mod2(gmp_mul(NumberTheory::inverse_mod($k, $n), gmp_Utils::gmp_mod2(gmp_add($hash, gmp_mul($this->secret_multiplier, $r)), $n)), $n);
if (gmp_cmp($s, 0) == 0) {
throw new ErrorExcpetion("error: random number S = 0<br />");
}
return new Signature($r, $s);
} else {
if (extension_loaded('bcmath') && USE_EXT == 'BCMATH') {
$G = $this->public_key->getGenerator();
$n = $G->getOrder();
$k = bcmod($random_k, $n);
$p1 = Point::mul($k, $G);
$r = $p1->getX();
if (bccomp($r, 0) == 0) {
throw new ErrorException("error: random number R = 0 <br />");
}
$s = bcmod(bcmul(NumberTheory::inverse_mod($k, $n), bcmod(bcadd($hash, bcmul($this->secret_multiplier, $r)), $n)), $n);
if (bccomp($s, 0) == 0) {
throw new ErrorExcpetion("error: random number S = 0<br />");
}
return new Signature($r, $s);
} else {
throw new ErrorException("Please install BCMATH or GMP");
}
}
}
public function verifies($hash, Signature $signature)
{
if (extension_loaded('gmp') && USE_EXT == 'GMP') {
$G = $this->generator;
$n = $this->generator->getOrder();
$point = $this->point;
$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;
}
$c = NumberTheory::inverse_mod($s, $n);
$u1 = gmp_Utils::gmp_mod2(gmp_mul($hash, $c), $n);
$u2 = gmp_Utils::gmp_mod2(gmp_mul($r, $c), $n);
$xy = Point::add(Point::mul($u1, $G), Point::mul($u2, $point));
$v = gmp_Utils::gmp_mod2($xy->getX(), $n);
if (gmp_cmp($v, $r) == 0) {
return true;
} else {
return false;
}
} else {
if (extension_loaded('bcmath') && USE_EXT == 'BCMATH') {
$G = $this->generator;
$n = $this->generator->getOrder();
$point = $this->point;
$r = $signature->getR();
$s = $signature->getS();
if (bccomp($r, 1) == -1 || bccomp($r, bcsub($n, 1)) == 1) {
return false;
}
if (bccomp($s, 1) == -1 || bccomp($s, bcsub($n, 1)) == 1) {
return false;
}
$c = NumberTheory::inverse_mod($s, $n);
$u1 = bcmod(bcmul($hash, $c), $n);
$u2 = bcmod(bcmul($r, $c), $n);
$xy = Point::add(Point::mul($u1, $G), Point::mul($u2, $point));
$v = bcmod($xy->getX(), $n);
if (bccomp($v, $r) == 0) {
return true;
} else {
return false;
}
} else {
throw new ErrorException("Please install BCMATH or GMP");
}
}
}
public static function bcmath_multInverseModP($verbose = false)
{
$start_time = microtime(true);
$n_tests = 0;
for ($i = 0; $i < 100; $i++) {
$m = rand(20, 10000);
for ($j = 0; $j < 100; $j++) {
$a = rand(1, $m - 1);
if (NumberTheory::gcd2($a, $m) == 1) {
$n_tests++;
$inv = NumberTheory::inverse_mod($a, $m);
if ($inv <= 0 || $inv >= $m || $a * $inv % $m != 1) {
$error_tally++;
print "{$inv} = inverse_mod( {$a}, {$m} ) is wrong.<br />\n";
flush();
} else {
if ($verbose) {
print "{$inv} = inverse_mod( {$a}, {$m} ) is CORRECT.<br />\n";
}
flush();
}
}
}
}
$end_time = microtime(true);
$time_res = $end_time - $start_time;
echo "<br />Multiplicative inverse mod arbitrary primes took: " . $time_res . " seconds. <br />";
flush();
}
public static function double(Point $p1)
{
if (extension_loaded('gmp') && USE_EXT == 'GMP') {
$p = $p1->curve->getPrime();
$a = $p1->curve->getA();
$inverse = NumberTheory::inverse_mod(gmp_strval(gmp_mul(2, $p1->y)), $p);
$three_x2 = gmp_mul(3, gmp_pow($p1->x, 2));
$l = gmp_strval(gmp_Utils::gmp_mod2(gmp_mul(gmp_add($three_x2, $a), $inverse), $p));
$x3 = gmp_strval(gmp_Utils::gmp_mod2(gmp_sub(gmp_pow($l, 2), gmp_mul(2, $p1->x)), $p));
$y3 = gmp_strval(gmp_Utils::gmp_mod2(gmp_sub(gmp_mul($l, gmp_sub($p1->x, $x3)), $p1->y), $p));
if (gmp_cmp(0, $y3) > 0) {
$y3 = gmp_strval(gmp_add($p, $y3));
}
$p3 = new Point($p1->curve, $x3, $y3);
return $p3;
} elseif (extension_loaded('bcmath') && USE_EXT == 'BCMATH') {
$p = $p1->curve->getPrime();
$a = $p1->curve->getA();
$inverse = NumberTheory::inverse_mod(bcmul(2, $p1->y), $p);
$three_x2 = bcmul(3, bcpow($p1->x, 2));
$l = bcmod(bcmul(bcadd($three_x2, $a), $inverse), $p);
$x3 = bcmod(bcsub(bcpow($l, 2), bcmul(2, $p1->x)), $p);
$y3 = bcmod(bcsub(bcmul($l, bcsub($p1->x, $x3)), $p1->y), $p);
if (bccomp(0, $y3) == 1) {
$y3 = bcadd($p, $y3);
}
$p3 = new Point($p1->curve, $x3, $y3);
return $p3;
} else {
throw new ErrorException("Please install BCMATH or GMP");
}
}
/**
* Decompress Public Key
*
* Accepts a y_byte, 02 or 03 indicating whether the Y coordinate is
* odd or even, and $passpoint, which is simply a hexadecimal X coordinate.
* Using this data, it is possible to deconstruct the original
* uncompressed public key.
*
* @param $key
* @return array|bool
*/
public static function decompress_public_key($key)
{
$y_byte = substr($key, 0, 2);
$x_coordinate = substr($key, 2);
$x = gmp_strval(gmp_init($x_coordinate, 16), 10);
$curve = \SECcurve::curve_secp256k1();
$generator = \SECcurve::generator_secp256k1();
try {
$x3 = \NumberTheory::modular_exp($x, 3, $curve->getPrime());
$y2 = gmp_add($x3, $curve->getB());
$y0 = \NumberTheory::square_root_mod_prime(gmp_strval($y2, 10), $curve->getPrime());
if ($y0 == FALSE) {
return FALSE;
}
$y1 = gmp_strval(gmp_sub($curve->getPrime(), $y0), 10);
$y_coordinate = $y_byte == '02' ? \gmp_Utils::gmp_mod2(gmp_init($y0, 10), 2) == '0' ? $y0 : $y1 : (\gmp_Utils::gmp_mod2(gmp_init($y0, 10), 2) !== '0' ? $y0 : $y1);
$y_coordinate = str_pad(gmp_strval($y_coordinate, 16), 64, '0', STR_PAD_LEFT);
$point = new \Point($curve, gmp_strval(gmp_init($x_coordinate, 16), 10), gmp_strval(gmp_init($y_coordinate, 16), 10), $generator->getOrder());
} catch (\Exception $e) {
return FALSE;
}
return array('x' => $x_coordinate, 'y' => $y_coordinate, 'point' => $point, 'public_key' => '04' . $x_coordinate . $y_coordinate);
}
public function decompress_public_key($key)
{
// Initialize
$y_byte = substr($key, 0, 2);
$x_coordinate = substr($key, 2);
// Set variables
$x = gmp_strval(gmp_init($x_coordinate, 16), 10);
$curve = SECcurve::curve_secp256k1();
$generator = SECcurve::generator_secp256k1();
// Decode
try {
$x3 = NumberTheory::modular_exp($x, 3, $curve->getPrime());
$y2 = gmp_add($x3, $curve->getB());
$y0 = NumberTheory::square_root_mod_prime(gmp_strval($y2, 10), $curve->getPrime());
if ($y0 === false) {
return false;
}
$y1 = gmp_strval(gmp_sub($curve->getPrime(), $y0), 10);
$y_coordinate = $y_byte == '02' ? gmp_Utils::gmp_mod2(gmp_init($y0, 10), 2) == '0' ? $y0 : $y1 : (gmp_Utils::gmp_mod2(gmp_init($y0, 10), 2) !== '0' ? $y0 : $y1);
$y_coordinate = str_pad(gmp_strval($y_coordinate, 16), 64, '0', STR_PAD_LEFT);
$point = new Point($curve, gmp_strval(gmp_init($x_coordinate, 16), 10), gmp_strval(gmp_init($y_coordinate, 16), 10), $generator->getOrder());
} catch (Exception $e) {
return false;
}
// Return
return array('x' => $x_coordinate, 'y' => $y_coordinate, 'point' => $point, 'public_key' => '04' . $x_coordinate . $y_coordinate);
}
public static function is_prime($n)
{
if (extension_loaded('gmp') && USE_EXT == 'GMP') {
return gmp_prob_prime($n);
} else {
if (extension_loaded('bcmath') && USE_EXT == 'BCMATH') {
self::$miller_rabin_test_count = 0;
$t = 40;
$k = 0;
$m = bcsub($n, 1);
while (bcmod($m, 2) == 0) {
$k = bcadd($k, 1);
$m = bcdiv($m, 2);
}
for ($i = 0; $i < $t; $i++) {
$a = bcmath_Utils::bcrand(1, bcsub($n, 1));
$b0 = self::modular_exp($a, $m, $n);
if ($b0 != 1 && $b0 != bcsub($n, 1)) {
$j = 1;
while ($j <= $k - 1 && $b0 != bcsub($n, 1)) {
$b0 = self::modular_exp($b0, 2, $n);
if ($b0 == 1) {
self::$miller_rabin_test_count = $i + 1;
return false;
}
$j++;
}
if ($b0 != bcsub($n, 1)) {
self::$miller_rabin_test_count = $i + 1;
return false;
}
}
}
return true;
} else {
throw new ErrorException("Please install BCMATH or GMP");
}
}
}
