/**
* @param string $byteString
* @param null|integer $byteSize
* @param MathAdapterInterface $math
* @throws \Exception
*/
public function __construct($byteString = '', $byteSize = null, MathAdapterInterface $math = null)
{
$this->math = $math ?: EccFactory::getAdapter();
if ($byteSize !== null) {
// Check the integer doesn't overflow its supposed size
if ($this->math->cmp(strlen($byteString), $byteSize) > 0) {
throw new \Exception('Byte string exceeds maximum size');
}
} else {
$byteSize = strlen($byteString);
}
$this->size = $byteSize;
$this->buffer = $byteString;
}
/**
* Parse $bytes bytes from the string, and return the obtained buffer
*
* @param integer $bytes
* @param bool $flipBytes
* @return Buffer
* @throws \Exception
*/
public function readBytes($bytes, $flipBytes = false)
{
$string = substr($this->string, $this->getPosition(), $bytes);
$length = strlen($string);
if ($length == 0) {
throw new ParserOutOfRange('Could not parse string of required length (empty)');
} elseif ($this->math->cmp($length, $bytes) !== 0) {
throw new ParserOutOfRange('Could not parse string of required length (too short)');
}
$this->position += $bytes;
if ($flipBytes) {
$string = Buffertools::flipBytes($string);
}
return new Buffer($string, $length, $this->math);
}
/**
* Initialize a new instance.
*
* @param MathAdapterInterface $adapter
* @param GeneratorPoint $generator
* @param PointInterface $point
* @throws \LogicException
* @throws \RuntimeException
*/
public function __construct(MathAdapterInterface $adapter, GeneratorPoint $generator, PointInterface $point)
{
$this->curve = $generator->getCurve();
$this->generator = $generator;
$this->point = $point;
$this->adapter = $adapter;
$n = $generator->getOrder();
if ($n == null) {
throw new \LogicException("Generator must have order.");
}
if (!$point->mul($n)->isInfinity()) {
throw new \RuntimeException("Generator point order is bad.");
}
if ($adapter->cmp($point->getX(), 0) < 0 || $adapter->cmp($n, $point->getX()) <= 0 || $adapter->cmp($point->getY(), 0) < 0 || $adapter->cmp($n, $point->getY()) <= 0) {
throw new \RuntimeException("Generator point has x and y out of range.");
}
}
/**
* {@inheritDoc}
* @see \Mdanter\Ecc\EcMathInterface::cmp()
*/
public function cmp($input)
{
$type = $this->identify($input);
if ($this->dataType == 'point' && $type == 'point') {
return $this->data->cmp($input);
}
if ($this->dataType == 'int' && $type == 'int') {
return $this->math->cmp($this->data, $input);
}
throw new \LogicException('Cannot compare values of different types');
}
/**
* Returns the number of bits used to store this number. Non-singicant upper bits are not counted.
*
* @param MathAdapterInterface $adapter
* @param int|string $x
* @return number
*
* @link https://www.openssl.org/docs/crypto/BN_num_bytes.html
*/
public static function bnNumBits(MathAdapterInterface $adapter, $x)
{
if ($adapter->cmp($x, '0') == 0) {
return 0;
}
$log2 = 0;
while ($x = $adapter->rightShift($x, 1)) {
$log2++;
}
return $log2 + 1;
}
/**
* {@inheritDoc}
* @see \Mdanter\Ecc\PointInterface::mul()
*/
public function mul($n)
{
if ($this->isInfinity()) {
return $this->curve->getInfinity();
}
if ($this->adapter->cmp($this->order, '0') > 0) {
$n = $this->adapter->mod($n, $this->order);
}
if ($this->adapter->cmp($n, '0') == 0) {
return $this->curve->getInfinity();
}
$r = [$this->curve->getInfinity(), clone $this];
$n = $this->adapter->baseConvert($n, 10, 2);
$k = strlen($n);
for ($i = 0; $i < $k; $i++) {
$j = $n[$i];
$this->cswap($r[0], $r[1], $j ^ 1);
$r[0] = $r[0]->add($r[1]);
$r[1] = $r[1]->getDouble();
$this->cswap($r[0], $r[1], $j ^ 1);
}
$r[0]->validate();
return $r[0];
}
/**
* @param $integer
* @param $bitSize
* @return bool
*/
public function isNegative($integer, $bitSize)
{
return $this->math->cmp($this->math->rightShift($integer, $this->fixSize($bitSize)), '1') == 0;
}
