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administrator/components/com_akeebabackup/webpush/ECC/BigInteger.php

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+<?php
+/**
+ * Akeeba WebPush
+ *
+ * An abstraction layer for easier implementation of WebPush in Joomla components.
+ *
+ * @copyright (c) 2022 Akeeba Ltd
+ * @license   GNU GPL v3 or later; see LICENSE.txt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Akeeba\WebPush\ECC;
+
+use Brick\Math\BigInteger as BrickBigInteger;
+use InvalidArgumentException;
+use function chr;
+
+/**
+ * This class is copied verbatim from the JWT Framework by Spomky Labs.
+ *
+ * You can find the original code at https://github.com/web-token/jwt-framework
+ *
+ * The original file has the following copyright notice:
+ *
+ * =====================================================================================================================
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2020 Spomky-Labs
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE-SPOMKY.txt file for details.
+ *
+ * =====================================================================================================================
+ *
+ * @internal
+ */
+class BigInteger
+{
+    /**
+     * Holds the BigInteger's value.
+     *
+     * @var BrickBigInteger
+     */
+    private $value;
+
+    private function __construct(BrickBigInteger $value)
+    {
+        $this->value = $value;
+    }
+
+    /**
+     * @return BigInteger
+     */
+    public static function createFromBinaryString(string $value): self
+    {
+        $res = unpack('H*', $value);
+        if (false === $res) {
+            throw new InvalidArgumentException('Unable to convert the value');
+        }
+        $data = current($res);
+
+        return new self(BrickBigInteger::fromBase($data, 16));
+    }
+
+    /**
+     * @return BigInteger
+     */
+    public static function createFromDecimal(int $value): self
+    {
+        return new self(BrickBigInteger::of($value));
+    }
+
+    /**
+     * @return BigInteger
+     */
+    public static function createFromBigInteger(BrickBigInteger $value): self
+    {
+        return new self($value);
+    }
+
+    /**
+     * Converts a BigInteger to a binary string.
+     */
+    public function toBytes(): string
+    {
+        if ($this->value->isEqualTo(BrickBigInteger::zero())) {
+            return '';
+        }
+
+        $temp = $this->value->toBase(16);
+        $temp = 0 !== (mb_strlen($temp, '8bit') & 1) ? '0'.$temp : $temp;
+        $temp = hex2bin($temp);
+        if (false === $temp) {
+            throw new InvalidArgumentException('Unable to convert the value into bytes');
+        }
+
+        return ltrim($temp, chr(0));
+    }
+
+    /**
+     * Adds two BigIntegers.
+     *
+     *  @param BigInteger $y
+     *
+     *  @return BigInteger
+     */
+    public function add(self $y): self
+    {
+        $value = $this->value->plus($y->value);
+
+        return new self($value);
+    }
+
+    /**
+     * Subtracts two BigIntegers.
+     *
+     *  @param BigInteger $y
+     *
+     *  @return BigInteger
+     */
+    public function subtract(self $y): self
+    {
+        $value = $this->value->minus($y->value);
+
+        return new self($value);
+    }
+
+    /**
+     * Multiplies two BigIntegers.
+     *
+     * @param BigInteger $x
+     *
+     *  @return BigInteger
+     */
+    public function multiply(self $x): self
+    {
+        $value = $this->value->multipliedBy($x->value);
+
+        return new self($value);
+    }
+
+    /**
+     * Divides two BigIntegers.
+     *
+     * @param BigInteger $x
+     *
+     *  @return BigInteger
+     */
+    public function divide(self $x): self
+    {
+        $value = $this->value->dividedBy($x->value);
+
+        return new self($value);
+    }
+
+    /**
+     * Performs modular exponentiation.
+     *
+     * @param BigInteger $e
+     * @param BigInteger $n
+     *
+     * @return BigInteger
+     */
+    public function modPow(self $e, self $n): self
+    {
+        $value = $this->value->modPow($e->value, $n->value);
+
+        return new self($value);
+    }
+
+    /**
+     * Performs modular exponentiation.
+     *
+     * @param BigInteger $d
+     *
+     * @return BigInteger
+     */
+    public function mod(self $d): self
+    {
+        $value = $this->value->mod($d->value);
+
+        return new self($value);
+    }
+
+    public function modInverse(BigInteger $m): BigInteger
+    {
+        return new self($this->value->modInverse($m->value));
+    }
+
+    /**
+     * Compares two numbers.
+     *
+     * @param BigInteger $y
+     */
+    public function compare(self $y): int
+    {
+        return $this->value->compareTo($y->value);
+    }
+
+    /**
+     * @param BigInteger $y
+     */
+    public function equals(self $y): bool
+    {
+        return $this->value->isEqualTo($y->value);
+    }
+
+    /**
+     * @param BigInteger $y
+     *
+     * @return BigInteger
+     */
+    public static function random(self $y): self
+    {
+        return new self(BrickBigInteger::randomRange(0, $y->value));
+    }
+
+    /**
+     * @param BigInteger $y
+     *
+     * @return BigInteger
+     */
+    public function gcd(self $y): self
+    {
+        return new self($this->value->gcd($y->value));
+    }
+
+    /**
+     * @param BigInteger $y
+     */
+    public function lowerThan(self $y): bool
+    {
+        return $this->value->isLessThan($y->value);
+    }
+
+    public function isEven(): bool
+    {
+        return $this->value->isEven();
+    }
+
+    public function get(): BrickBigInteger
+    {
+        return $this->value;
+    }
+}

administrator/components/com_akeebabackup/webpush/ECC/Curve.php

@@ -0,0 +1,353 @@
+<?php
+/**
+ * Akeeba WebPush
+ *
+ * An abstraction layer for easier implementation of WebPush in Joomla components.
+ *
+ * @copyright (c) 2022 Akeeba Ltd
+ * @license   GNU GPL v3 or later; see LICENSE.txt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Akeeba\WebPush\ECC;
+
+use Brick\Math\BigInteger;
+use RuntimeException;
+use function is_null;
+
+/**
+ * This class is copied verbatim from the JWT Framework by Spomky Labs.
+ *
+ * You can find the original code at https://github.com/web-token/jwt-framework
+ *
+ * The original file has the following copyright notice:
+ *
+ * =====================================================================================================================
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2020 Spomky-Labs
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE-SPOMKY.txt file for details.
+ *
+ * =====================================================================================================================
+ *
+ * @internal
+ */
+class Curve
+{
+    /**
+     * Elliptic curve over the field of integers modulo a prime.
+     *
+     * @var BigInteger
+     */
+    private $a;
+
+    /**
+     * @var BigInteger
+     */
+    private $b;
+
+    /**
+     * @var BigInteger
+     */
+    private $prime;
+
+    /**
+     * Binary length of keys associated with these curve parameters.
+     *
+     * @var int
+     */
+    private $size;
+
+    /**
+     * @var Point
+     */
+    private $generator;
+
+    public function __construct(int $size, BigInteger $prime, BigInteger $a, BigInteger $b, Point $generator)
+    {
+        $this->size = $size;
+        $this->prime = $prime;
+        $this->a = $a;
+        $this->b = $b;
+        $this->generator = $generator;
+    }
+
+    public function __toString(): string
+    {
+        return 'curve('.Math::toString($this->getA()).', '.Math::toString($this->getB()).', '.Math::toString($this->getPrime()).')';
+    }
+
+    public function getA(): BigInteger
+    {
+        return $this->a;
+    }
+
+    public function getB(): BigInteger
+    {
+        return $this->b;
+    }
+
+    public function getPrime(): BigInteger
+    {
+        return $this->prime;
+    }
+
+    public function getSize(): int
+    {
+        return $this->size;
+    }
+
+    /**
+     * @throws RuntimeException if the curve does not contain the point
+     */
+    public function getPoint(BigInteger $x, BigInteger $y, ?BigInteger $order = null): Point
+    {
+        if (!$this->contains($x, $y)) {
+            throw new RuntimeException('Curve '.$this->__toString().' does not contain point ('.Math::toString($x).', '.Math::toString($y).')');
+        }
+        $point = Point::create($x, $y, $order);
+        if (!is_null($order)) {
+            $mul = $this->mul($point, $order);
+            if (!$mul->isInfinity()) {
+                throw new RuntimeException('SELF * ORDER MUST EQUAL INFINITY.');
+            }
+        }
+
+        return $point;
+    }
+
+    /**
+     * @throws RuntimeException if the coordinates are out of range
+     */
+    public function getPublicKeyFrom(BigInteger $x, BigInteger $y): PublicKey
+    {
+        $zero = BigInteger::zero();
+        if ($x->compareTo($zero) < 0 || $y->compareTo($zero) < 0 || $this->generator->getOrder()->compareTo($x) <= 0 || $this->generator->getOrder()->compareTo($y) <= 0) {
+            throw new RuntimeException('Generator point has x and y out of range.');
+        }
+        $point = $this->getPoint($x, $y);
+
+        return new PublicKey($point);
+    }
+
+    public function contains(BigInteger $x, BigInteger $y): bool
+    {
+        return Math::equals(
+            ModularArithmetic::sub(
+                $y->power(2),
+                Math::add(
+                    Math::add(
+                        $x->power(3),
+                        $this->getA()->multipliedBy($x)
+                    ),
+                    $this->getB()
+                ),
+                $this->getPrime()
+            ),
+            BigInteger::zero()
+        );
+    }
+
+    public function add(Point $one, Point $two): Point
+    {
+        if ($two->isInfinity()) {
+            return clone $one;
+        }
+
+        if ($one->isInfinity()) {
+            return clone $two;
+        }
+
+        if ($two->getX()->isEqualTo($one->getX())) {
+            if ($two->getY()->isEqualTo($one->getY())) {
+                return $this->getDouble($one);
+            }
+
+            return Point::infinity();
+        }
+
+        $slope = ModularArithmetic::div(
+            $two->getY()->minus($one->getY()),
+            $two->getX()->minus($one->getX()),
+            $this->getPrime()
+        );
+
+        $xR = ModularArithmetic::sub(
+            $slope->power(2)->minus($one->getX()),
+            $two->getX(),
+            $this->getPrime()
+        );
+
+        $yR = ModularArithmetic::sub(
+            $slope->multipliedBy($one->getX()->minus($xR)),
+            $one->getY(),
+            $this->getPrime()
+        );
+
+        return $this->getPoint($xR, $yR, $one->getOrder());
+    }
+
+    public function mul(Point $one, BigInteger $n): Point
+    {
+        if ($one->isInfinity()) {
+            return Point::infinity();
+        }
+
+        /** @var BigInteger $zero */
+        $zero = BigInteger::zero();
+        if ($one->getOrder()->compareTo($zero) > 0) {
+            $n = $n->mod($one->getOrder());
+        }
+
+        if ($n->isEqualTo($zero)) {
+            return Point::infinity();
+        }
+
+        /** @var Point[] $r */
+        $r = [
+            Point::infinity(),
+            clone $one,
+        ];
+
+        $k = $this->getSize();
+        $n1 = str_pad(Math::baseConvert(Math::toString($n), 10, 2), $k, '0', STR_PAD_LEFT);
+
+        for ($i = 0; $i < $k; ++$i) {
+            $j = $n1[$i];
+            Point::cswap($r[0], $r[1], $j ^ 1);
+            $r[0] = $this->add($r[0], $r[1]);
+            $r[1] = $this->getDouble($r[1]);
+            Point::cswap($r[0], $r[1], $j ^ 1);
+        }
+
+        $this->validate($r[0]);
+
+        return $r[0];
+    }
+
+    /**
+     * @param Curve $other
+     */
+    public function cmp(self $other): int
+    {
+        $equal = $this->getA()->isEqualTo($other->getA())
+                 && $this->getB()->isEqualTo($other->getB())
+                 && $this->getPrime()->isEqualTo($other->getPrime());
+
+        return $equal ? 0 : 1;
+    }
+
+    /**
+     * @param Curve $other
+     */
+    public function equals(self $other): bool
+    {
+        return 0 === $this->cmp($other);
+    }
+
+    public function getDouble(Point $point): Point
+    {
+        if ($point->isInfinity()) {
+            return Point::infinity();
+        }
+
+        $a = $this->getA();
+        $threeX2 = BigInteger::of(3)->multipliedBy($point->getX()->power(2));
+
+        $tangent = ModularArithmetic::div(
+            $threeX2->plus($a),
+            BigInteger::of(2)->multipliedBy($point->getY()),
+            $this->getPrime()
+        );
+
+        $x3 = ModularArithmetic::sub(
+            $tangent->power(2),
+            BigInteger::of(2)->multipliedBy($point->getX()),
+            $this->getPrime()
+        );
+
+        $y3 = ModularArithmetic::sub(
+            $tangent->multipliedBy($point->getX()->minus($x3)),
+            $point->getY(),
+            $this->getPrime()
+        );
+
+        return $this->getPoint($x3, $y3, $point->getOrder());
+    }
+
+    public function createPrivateKey(): PrivateKey
+    {
+        return PrivateKey::create($this->generate());
+    }
+
+    public function createPublicKey(PrivateKey $privateKey): PublicKey
+    {
+        $point = $this->mul($this->generator, $privateKey->getSecret());
+
+        return new PublicKey($point);
+    }
+
+    public function getGenerator(): Point
+    {
+        return $this->generator;
+    }
+
+    /**
+     * @throws RuntimeException if the point is invalid
+     */
+    private function validate(Point $point): void
+    {
+        if (!$point->isInfinity() && !$this->contains($point->getX(), $point->getY())) {
+            throw new RuntimeException('Invalid point');
+        }
+    }
+
+    private function generate(): BigInteger
+    {
+        $max = $this->generator->getOrder();
+        $numBits = $this->bnNumBits($max);
+        $numBytes = (int) ceil($numBits / 8);
+        // Generate an integer of size >= $numBits
+        $bytes = BigInteger::randomBits($numBytes);
+        $mask = BigInteger::of(2)->power($numBits)->minus(1);
+
+        return $bytes->and($mask);
+    }
+
+    /**
+     * Returns the number of bits used to store this number. Non-significant upper bits are not counted.
+     *
+     * @see https://www.openssl.org/docs/crypto/BN_num_bytes.html
+     */
+    private function bnNumBits(BigInteger $x): int
+    {
+        $zero = BigInteger::of(0);
+        if ($x->isEqualTo($zero)) {
+            return 0;
+        }
+        $log2 = 0;
+        while (!$x->isEqualTo($zero)) {
+            $x = $x->shiftedRight(1);
+            ++$log2;
+        }
+
+        return $log2;
+    }
+}

administrator/components/com_akeebabackup/webpush/ECC/Math.php

@@ -0,0 +1,77 @@
+<?php
+/**
+ * Akeeba WebPush
+ *
+ * An abstraction layer for easier implementation of WebPush in Joomla components.
+ *
+ * @copyright (c) 2022 Akeeba Ltd
+ * @license   GNU GPL v3 or later; see LICENSE.txt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Akeeba\WebPush\ECC;
+
+use Akeeba\WebPush\ECC\BigInteger as CoreBigInteger;
+use Brick\Math\BigInteger;
+
+/**
+ * This class is copied verbatim from the JWT Framework by Spomky Labs.
+ *
+ * You can find the original code at https://github.com/web-token/jwt-framework
+ *
+ * The original file has the following copyright notice:
+ *
+ * =====================================================================================================================
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2020 Spomky-Labs
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE-SPOMKY.txt file for details.
+ *
+ * =====================================================================================================================
+ *
+ * @internal
+ */
+class Math
+{
+    public static function equals(BigInteger $first, BigInteger $other): bool
+    {
+        return $first->isEqualTo($other);
+    }
+
+    public static function add(BigInteger $augend, BigInteger $addend): BigInteger
+    {
+        return $augend->plus($addend);
+    }
+
+    public static function toString(BigInteger $value): string
+    {
+        return $value->toBase(10);
+    }
+
+    public static function inverseMod(BigInteger $a, BigInteger $m): BigInteger
+    {
+        return CoreBigInteger::createFromBigInteger($a)->modInverse(CoreBigInteger::createFromBigInteger($m))->get();
+    }
+
+    public static function baseConvert(string $number, int $from, int $to): string
+    {
+        return BigInteger::fromBase($number, $from)->toBase($to);
+    }
+}

administrator/components/com_akeebabackup/webpush/ECC/ModularArithmetic.php

@@ -0,0 +1,66 @@
+<?php
+/**
+ * Akeeba WebPush
+ *
+ * An abstraction layer for easier implementation of WebPush in Joomla components.
+ *
+ * @copyright (c) 2022 Akeeba Ltd
+ * @license   GNU GPL v3 or later; see LICENSE.txt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Akeeba\WebPush\ECC;
+
+use Brick\Math\BigInteger;
+
+/**
+ * This class is copied verbatim from the JWT Framework by Spomky Labs.
+ *
+ * You can find the original code at https://github.com/web-token/jwt-framework
+ *
+ * The original file has the following copyright notice:
+ *
+ * =====================================================================================================================
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2020 Spomky-Labs
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE-SPOMKY.txt file for details.
+ *
+ * =====================================================================================================================
+ *
+ * @internal
+ */
+class ModularArithmetic
+{
+    public static function sub(BigInteger $minuend, BigInteger $subtrahend, BigInteger $modulus): BigInteger
+    {
+        return $minuend->minus($subtrahend)->mod($modulus);
+    }
+
+    public static function mul(BigInteger $multiplier, BigInteger $muliplicand, BigInteger $modulus): BigInteger
+    {
+        return $multiplier->multipliedBy($muliplicand)->mod($modulus);
+    }
+
+    public static function div(BigInteger $dividend, BigInteger $divisor, BigInteger $modulus): BigInteger
+    {
+        return self::mul($dividend, Math::inverseMod($divisor, $modulus), $modulus);
+    }
+}

administrator/components/com_akeebabackup/webpush/ECC/Point.php

@@ -0,0 +1,165 @@
+<?php
+/**
+ * Akeeba WebPush
+ *
+ * An abstraction layer for easier implementation of WebPush in Joomla components.
+ *
+ * @copyright (c) 2022 Akeeba Ltd
+ * @license   GNU GPL v3 or later; see LICENSE.txt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Akeeba\WebPush\ECC;
+
+use Brick\Math\BigInteger;
+
+/**
+ * This class is copied verbatim from the JWT Framework by Spomky Labs.
+ *
+ * You can find the original code at https://github.com/web-token/jwt-framework
+ *
+ * The original file has the following copyright notice:
+ *
+ * =====================================================================================================================
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2020 Spomky-Labs
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE-SPOMKY.txt file for details.
+ *
+ * =====================================================================================================================
+ *
+ * *********************************************************************
+ * Copyright (C) 2012 Matyas Danter.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ * ***********************************************************************
+ *
+ * @internal
+ */
+class Point
+{
+    /**
+     * @var BigInteger
+     */
+    private $x;
+
+    /**
+     * @var BigInteger
+     */
+    private $y;
+
+    /**
+     * @var BigInteger
+     */
+    private $order;
+
+    /**
+     * @var bool
+     */
+    private $infinity = false;
+
+    private function __construct(BigInteger $x, BigInteger $y, BigInteger $order, bool $infinity = false)
+    {
+        $this->x = $x;
+        $this->y = $y;
+        $this->order = $order;
+        $this->infinity = $infinity;
+    }
+
+    public static function create(BigInteger $x, BigInteger $y, ?BigInteger $order = null): self
+    {
+        return new self($x, $y, $order ?? BigInteger::zero());
+    }
+
+    public static function infinity(): self
+    {
+        $zero = BigInteger::zero();
+
+        return new self($zero, $zero, $zero, true);
+    }
+
+    public function isInfinity(): bool
+    {
+        return $this->infinity;
+    }
+
+    public function getOrder(): BigInteger
+    {
+        return $this->order;
+    }
+
+    public function getX(): BigInteger
+    {
+        return $this->x;
+    }
+
+    public function getY(): BigInteger
+    {
+        return $this->y;
+    }
+
+    public static function cswap(self $a, self $b, int $cond): void
+    {
+        self::cswapBigInteger($a->x, $b->x, $cond);
+        self::cswapBigInteger($a->y, $b->y, $cond);
+        self::cswapBigInteger($a->order, $b->order, $cond);
+        self::cswapBoolean($a->infinity, $b->infinity, $cond);
+    }
+
+    private static function cswapBoolean(bool &$a, bool &$b, int $cond): void
+    {
+        $sa = BigInteger::of((int) $a);
+        $sb = BigInteger::of((int) $b);
+
+        self::cswapBigInteger($sa, $sb, $cond);
+
+        $a = (bool) $sa->toBase(10);
+        $b = (bool) $sb->toBase(10);
+    }
+
+    private static function cswapBigInteger(BigInteger &$sa, BigInteger &$sb, int $cond): void
+    {
+        $size = max(mb_strlen($sa->toBase(2), '8bit'), mb_strlen($sb->toBase(2), '8bit'));
+        $mask = (string) (1 - $cond);
+        $mask = str_pad('', $size, $mask, STR_PAD_LEFT);
+        $mask = BigInteger::fromBase($mask, 2);
+        $taA = $sa->and($mask);
+        $taB = $sb->and($mask);
+        $sa = $sa->xor($sb)->xor($taB);
+        $sb = $sa->xor($sb)->xor($taA);
+        $sa = $sa->xor($sb)->xor($taB);
+    }
+}

administrator/components/com_akeebabackup/webpush/ECC/PrivateKey.php

@@ -0,0 +1,93 @@
+<?php
+/**
+ * Akeeba WebPush
+ *
+ * An abstraction layer for easier implementation of WebPush in Joomla components.
+ *
+ * @copyright (c) 2022 Akeeba Ltd
+ * @license   GNU GPL v3 or later; see LICENSE.txt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Akeeba\WebPush\ECC;
+
+use Brick\Math\BigInteger;
+
+/**
+ * This class is copied verbatim from the JWT Framework by Spomky Labs.
+ *
+ * You can find the original code at https://github.com/web-token/jwt-framework
+ *
+ * The original file has the following copyright notice:
+ *
+ * =====================================================================================================================
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2020 Spomky-Labs
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE-SPOMKY.txt file for details.
+ *
+ * =====================================================================================================================
+ *
+ * *********************************************************************
+ * Copyright (C) 2012 Matyas Danter.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ * ***********************************************************************
+ *
+ * @internal
+ */
+class PrivateKey
+{
+    /**
+     * @var BigInteger
+     */
+    private $secret;
+
+    private function __construct(BigInteger $secret)
+    {
+        $this->secret = $secret;
+    }
+
+    public static function create(BigInteger $secret): self
+    {
+        return new self($secret);
+    }
+
+    public function getSecret(): BigInteger
+    {
+        return $this->secret;
+    }
+}

administrator/components/com_akeebabackup/webpush/ECC/PublicKey.php

@@ -0,0 +1,86 @@
+<?php
+/**
+ * Akeeba WebPush
+ *
+ * An abstraction layer for easier implementation of WebPush in Joomla components.
+ *
+ * @copyright (c) 2022 Akeeba Ltd
+ * @license   GNU GPL v3 or later; see LICENSE.txt
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+declare(strict_types=1);
+
+namespace Akeeba\WebPush\ECC;
+
+/**
+ * This class is copied verbatim from the JWT Framework by Spomky Labs.
+ *
+ * You can find the original code at https://github.com/web-token/jwt-framework
+ *
+ * The original file has the following copyright notice:
+ *
+ * =====================================================================================================================
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2020 Spomky-Labs
+ *
+ * This software may be modified and distributed under the terms
+ * of the MIT license.  See the LICENSE-SPOMKY.txt file for details.
+ *
+ * =====================================================================================================================
+ *
+ * *********************************************************************
+ * Copyright (C) 2012 Matyas Danter.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES
+ * OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ * ***********************************************************************
+ *
+ * @internal
+ */
+class PublicKey
+{
+    /**
+     * @var Point
+     */
+    private $point;
+
+    public function __construct(Point $point)
+    {
+        $this->point = $point;
+    }
+
+    public function getPoint(): Point
+    {
+        return $this->point;
+    }
+}