<?php

/**
 * Curve methods common to all curves
 *
 * PHP version 5 and 7
 *
 * @author    Jim Wigginton <terrafrost@php.net>
 * @copyright 2017 Jim Wigginton
 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
 * @link      http://pear.php.net/package/Math_BigInteger
 */

namespace phpseclib3\Crypt\EC\BaseCurves;

use phpseclib3\Math\BigInteger;

/**
 * Base
 *
 * @author  Jim Wigginton <terrafrost@php.net>
 */
abstract class Base
{
    /**
     * The Order
     *
     * @var BigInteger
     */
    protected $order;

    /**
     * Finite Field Integer factory
     *
     * @var \phpseclib3\Math\FiniteField\Integer
     */
    protected $factory;

    /**
     * Returns a random integer
     *
     * @return object
     */
    public function randomInteger()
    {
        return $this->factory->randomInteger();
    }

    /**
     * Converts a BigInteger to a \phpseclib3\Math\FiniteField\Integer integer
     *
     * @return object
     */
    public function convertInteger(BigInteger $x)
    {
        return $this->factory->newInteger($x);
    }

    /**
     * Returns the length, in bytes, of the modulo
     *
     * @return integer
     */
    public function getLengthInBytes()
    {
        return $this->factory->getLengthInBytes();
    }

    /**
     * Returns the length, in bits, of the modulo
     *
     * @return integer
     */
    public function getLength()
    {
        return $this->factory->getLength();
    }

    /**
     * Multiply a point on the curve by a scalar
     *
     * Uses the montgomery ladder technique as described here:
     *
     * https://en.wikipedia.org/wiki/Elliptic_curve_point_multiplication#Montgomery_ladder
     * https://github.com/phpecc/phpecc/issues/16#issuecomment-59176772
     *
     * @return array
     */
    public function multiplyPoint(array $p, BigInteger $d)
    {
        $alreadyInternal = isset($p[2]);
        $r = $alreadyInternal ?
            [[], $p] :
            [[], $this->convertToInternal($p)];

        $d = $d->toBits();
        for ($i = 0; $i < strlen($d); $i++) {
            $d_i = (int) $d[$i];
            $r[1 - $d_i] = $this->addPoint($r[0], $r[1]);
            $r[$d_i] = $this->doublePoint($r[$d_i]);
        }

        return $alreadyInternal ? $r[0] : $this->convertToAffine($r[0]);
    }

    /**
     * Creates a random scalar multiplier
     *
     * @return BigInteger
     */
    public function createRandomMultiplier()
    {
        static $one;
        if (!isset($one)) {
            $one = new BigInteger(1);
        }

        return BigInteger::randomRange($one, $this->order->subtract($one));
    }

    /**
     * Performs range check
     */
    public function rangeCheck(BigInteger $x)
    {
        static $zero;
        if (!isset($zero)) {
            $zero = new BigInteger();
        }

        if (!isset($this->order)) {
            throw new \RuntimeException('setOrder needs to be called before this method');
        }
        if ($x->compare($this->order) > 0 || $x->compare($zero) <= 0) {
            throw new \RangeException('x must be between 1 and the order of the curve');
        }
    }

    /**
     * Sets the Order
     */
    public function setOrder(BigInteger $order)
    {
        $this->order = $order;
    }

    /**
     * Returns the Order
     *
     * @return \phpseclib3\Math\BigInteger
     */
    public function getOrder()
    {
        return $this->order;
    }

    /**
     * Use a custom defined modular reduction function
     *
     * @return object
     */
    public function setReduction(callable $func)
    {
        $this->factory->setReduction($func);
    }

    /**
     * Returns the affine point
     *
     * @return object[]
     */
    public function convertToAffine(array $p)
    {
        return $p;
    }

    /**
     * Converts an affine point to a jacobian coordinate
     *
     * @return object[]
     */
    public function convertToInternal(array $p)
    {
        return $p;
    }

    /**
     * Negates a point
     *
     * @return object[]
     */
    public function negatePoint(array $p)
    {
        $temp = [
            $p[0],
            $p[1]->negate()
        ];
        if (isset($p[2])) {
            $temp[] = $p[2];
        }
        return $temp;
    }

    /**
     * Multiply and Add Points
     *
     * @return int[]
     */
    public function multiplyAddPoints(array $points, array $scalars)
    {
        $p1 = $this->convertToInternal($points[0]);
        $p2 = $this->convertToInternal($points[1]);
        $p1 = $this->multiplyPoint($p1, $scalars[0]);
        $p2 = $this->multiplyPoint($p2, $scalars[1]);
        $r = $this->addPoint($p1, $p2);
        return $this->convertToAffine($r);
    }
}

• [F] Base.php
  Delete
• [F] Binary.php
  Delete
• [F] KoblitzPrime.php
  Delete
• [F] Montgomery.php
  Delete
• [F] Prime.php
  Delete
• [F] TwistedEdwards.php
  Delete

Blog Section

Discover the Latest in Digital Payments and NFC Technology

Dive into our blog to explore the cutting-edge trends in digital payments and NFC technology. Stay updated on the innovations that are revolutionizing transactions, boosting security, and making payments quicker and more convenient. Learn how these advancements are shaping the future of financial interactions and driving the global transition towards a cashless world.

The Rise of Contactless Payments:...

In recent years, contactless payments have surged in popularity, driven...

Visit Blog

March 27, 2024

Enhancing Payment Security: The Role...

As digital transactions proliferate, ensuring robust payment security is more critical than ever. Two foundational...

Visit Blog

March 27, 2024

The Future of Digital Wallets:...

Digital wallets have fundamentally transformed how we manage money, offering a streamlined, secure, and highly...

Visit Blog

March 27, 2024