Subversion Repositories oidplus

<?php

/**

 * Pure-PHP implementation of ChaCha20.

 *

 * PHP version 5

 *

 * @author    Jim Wigginton <terrafrost@php.net>

 * @copyright 2019 Jim Wigginton

 * @license   http://www.opensource.org/licenses/mit-license.html  MIT License

 * @link      http://phpseclib.sourceforge.net

 */

namespace phpseclib3\Crypt;

use phpseclib3\Exception\BadDecryptionException;

use phpseclib3\Exception\InsufficientSetupException;

/**

 * Pure-PHP implementation of ChaCha20.

 *

 * @author  Jim Wigginton <terrafrost@php.net>

 */

class ChaCha20 extends Salsa20

{

    /**

     * The OpenSSL specific name of the cipher

     *

     * @var string

     */

    protected $cipher_name_openssl = 'chacha20';

    /**

     * Test for engine validity

     *

     * This is mainly just a wrapper to set things up for \phpseclib3\Crypt\Common\SymmetricKey::isValidEngine()

     *

     * @see \phpseclib3\Crypt\Common\SymmetricKey::__construct()

     * @param int $engine

     * @return bool

     */

    protected function isValidEngineHelper($engine)

    {

        switch ($engine) {

            case self::ENGINE_LIBSODIUM:

                // PHP 7.2.0 (30 Nov 2017) added support for libsodium

                // we could probably make it so that if $this->counter == 0 then the first block would be done with either OpenSSL

                // or PHP and then subsequent blocks would then be done with libsodium but idk - it's not a high priority atm

                // we could also make it so that if $this->counter == 0 and $this->continuousBuffer then do the first string

                // with libsodium and subsequent strings with openssl or pure-PHP but again not a high priority

                return function_exists('sodium_crypto_aead_chacha20poly1305_ietf_encrypt') &&

                       $this->key_length == 32 &&

                       (($this->usePoly1305 && !isset($this->poly1305Key) && $this->counter == 0) || $this->counter == 1) &&

                       !$this->continuousBuffer;

            case self::ENGINE_OPENSSL:

                // OpenSSL 1.1.0 (released 25 Aug 2016) added support for chacha20.

                // PHP didn't support OpenSSL 1.1.0 until 7.0.19 (11 May 2017)

                // if you attempt to provide openssl with a 128 bit key (as opposed to a 256 bit key) openssl will null

                // pad the key to 256 bits and still use the expansion constant for 256-bit keys. the fact that

                // openssl treats the IV as both the counter and nonce, however, let's us use openssl in continuous mode

                // whereas libsodium does not

                if ($this->key_length != 32) {

                    return false;

                }

        }

        return parent::isValidEngineHelper($engine);

    }

    /**

     * Encrypts a message.

     *

     * @see \phpseclib3\Crypt\Common\SymmetricKey::decrypt()

     * @see self::crypt()

     * @param string $plaintext

     * @return string $ciphertext

     */

    public function encrypt($plaintext)

    {

        $this->setup();

        if ($this->engine == self::ENGINE_LIBSODIUM) {

            return $this->encrypt_with_libsodium($plaintext);

        }

        return parent::encrypt($plaintext);

    }

    /**

     * Decrypts a message.

     *

     * $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).

     * At least if the continuous buffer is disabled.

     *

     * @see \phpseclib3\Crypt\Common\SymmetricKey::encrypt()

     * @see self::crypt()

     * @param string $ciphertext

     * @return string $plaintext

     */

    public function decrypt($ciphertext)

    {

        $this->setup();

        if ($this->engine == self::ENGINE_LIBSODIUM) {

            return $this->decrypt_with_libsodium($ciphertext);

        }

        return parent::decrypt($ciphertext);

    }

    /**

     * Encrypts a message with libsodium

     *

     * @see self::encrypt()

     * @param string $plaintext

     * @return string $text

     */

    private function encrypt_with_libsodium($plaintext)

    {

        $params = [$plaintext, $this->aad, $this->nonce, $this->key];

        $ciphertext = strlen($this->nonce) == 8 ?

            sodium_crypto_aead_chacha20poly1305_encrypt(...$params) :

            sodium_crypto_aead_chacha20poly1305_ietf_encrypt(...$params);

        if (!$this->usePoly1305) {

            return substr($ciphertext, 0, strlen($plaintext));

        }

        $newciphertext = substr($ciphertext, 0, strlen($plaintext));

        $this->newtag = $this->usingGeneratedPoly1305Key && strlen($this->nonce) == 12 ?

            substr($ciphertext, strlen($plaintext)) :

            $this->poly1305($newciphertext);

        return $newciphertext;

    }

    /**

     * Decrypts a message with libsodium

     *

     * @see self::decrypt()

     * @param string $ciphertext

     * @return string $text

     */

    private function decrypt_with_libsodium($ciphertext)

    {

        $params = [$ciphertext, $this->aad, $this->nonce, $this->key];

        if (isset($this->poly1305Key)) {

            if ($this->oldtag === false) {

                throw new InsufficientSetupException('Authentication Tag has not been set');

            }

            if ($this->usingGeneratedPoly1305Key && strlen($this->nonce) == 12) {

                $plaintext = sodium_crypto_aead_chacha20poly1305_ietf_decrypt(...$params);

                $this->oldtag = false;

                if ($plaintext === false) {

                    throw new BadDecryptionException('Derived authentication tag and supplied authentication tag do not match');

                }

                return $plaintext;

            }

            $newtag = $this->poly1305($ciphertext);

            if ($this->oldtag != substr($newtag, 0, strlen($this->oldtag))) {

                $this->oldtag = false;

                throw new BadDecryptionException('Derived authentication tag and supplied authentication tag do not match');

            }

            $this->oldtag = false;

        }

        $plaintext = strlen($this->nonce) == 8 ?

            sodium_crypto_aead_chacha20poly1305_encrypt(...$params) :

            sodium_crypto_aead_chacha20poly1305_ietf_encrypt(...$params);

        return substr($plaintext, 0, strlen($ciphertext));

    }

    /**

     * Sets the nonce.

     *

     * @param string $nonce

     */

    public function setNonce($nonce)

    {

        if (!is_string($nonce)) {

            throw new \UnexpectedValueException('The nonce should be a string');

        }

        /*

          from https://tools.ietf.org/html/rfc7539#page-7

          "Note also that the original ChaCha had a 64-bit nonce and 64-bit

           block count.  We have modified this here to be more consistent with

           recommendations in Section 3.2 of [RFC5116]."

         */

        switch (strlen($nonce)) {

            case 8:  // 64 bits

            case 12: // 96 bits

                break;

            default:

                throw new \LengthException('Nonce of size ' . strlen($nonce) . ' not supported by this algorithm. Only 64-bit nonces or 96-bit nonces are supported');

        }

        $this->nonce = $nonce;

        $this->changed = true;

        $this->setEngine();

    }

    /**

     * Setup the self::ENGINE_INTERNAL $engine

     *

     * (re)init, if necessary, the internal cipher $engine

     *

     * _setup() will be called each time if $changed === true

     * typically this happens when using one or more of following public methods:

     *

     * - setKey()

     *

     * - setNonce()

     *

     * - First run of encrypt() / decrypt() with no init-settings

     *

     * @see self::setKey()

     * @see self::setNonce()

     * @see self::disableContinuousBuffer()

     */

    protected function setup()

    {

        if (!$this->changed) {

            return;

        }

        $this->enbuffer = $this->debuffer = ['ciphertext' => '', 'counter' => $this->counter];

        $this->changed = $this->nonIVChanged = false;

        if ($this->nonce === false) {

            throw new InsufficientSetupException('No nonce has been defined');

        }

        if ($this->key === false) {

            throw new InsufficientSetupException('No key has been defined');

        }

        if ($this->usePoly1305 && !isset($this->poly1305Key)) {

            $this->usingGeneratedPoly1305Key = true;

            if ($this->engine == self::ENGINE_LIBSODIUM) {

                return;

            }

            $this->createPoly1305Key();

        }

        $key = $this->key;

        if (strlen($key) == 16) {

            $constant = 'expand 16-byte k';

            $key .= $key;

        } else {

            $constant = 'expand 32-byte k';

        }

        $this->p1 = $constant . $key;

        $this->p2 = $this->nonce;

        if (strlen($this->nonce) == 8) {

            $this->p2 = "\0\0\0\0" . $this->p2;

        }

    }

    /**

     * The quarterround function

     *

     * @param int $a

     * @param int $b

     * @param int $c

     * @param int $d

     */

    protected static function quarterRound(&$a, &$b, &$c, &$d)

    {

        // in https://datatracker.ietf.org/doc/html/rfc7539#section-2.1 the addition,

        // xor'ing and rotation are all on the same line so i'm keeping it on the same

        // line here as well

        // @codingStandardsIgnoreStart

        $a+= $b; $d = self::leftRotate(intval($d) ^ intval($a), 16);

        $c+= $d; $b = self::leftRotate(intval($b) ^ intval($c), 12);

        $a+= $b; $d = self::leftRotate(intval($d) ^ intval($a), 8);

        $c+= $d; $b = self::leftRotate(intval($b) ^ intval($c), 7);

        // @codingStandardsIgnoreEnd

    }

    /**

     * The doubleround function

     *

     * @param int $x0 (by reference)

     * @param int $x1 (by reference)

     * @param int $x2 (by reference)

     * @param int $x3 (by reference)

     * @param int $x4 (by reference)

     * @param int $x5 (by reference)

     * @param int $x6 (by reference)

     * @param int $x7 (by reference)

     * @param int $x8 (by reference)

     * @param int $x9 (by reference)

     * @param int $x10 (by reference)

     * @param int $x11 (by reference)

     * @param int $x12 (by reference)

     * @param int $x13 (by reference)

     * @param int $x14 (by reference)

     * @param int $x15 (by reference)

     */

    protected static function doubleRound(&$x0, &$x1, &$x2, &$x3, &$x4, &$x5, &$x6, &$x7, &$x8, &$x9, &$x10, &$x11, &$x12, &$x13, &$x14, &$x15)

    {

        // columnRound

        static::quarterRound($x0, $x4, $x8, $x12);

        static::quarterRound($x1, $x5, $x9, $x13);

        static::quarterRound($x2, $x6, $x10, $x14);

        static::quarterRound($x3, $x7, $x11, $x15);

        // rowRound

        static::quarterRound($x0, $x5, $x10, $x15);

        static::quarterRound($x1, $x6, $x11, $x12);

        static::quarterRound($x2, $x7, $x8, $x13);

        static::quarterRound($x3, $x4, $x9, $x14);

    }

    /**

     * The Salsa20 hash function function

     *

     * On my laptop this loop unrolled / function dereferenced version of parent::salsa20 encrypts 1mb of text in

     * 0.65s vs the 0.85s that it takes with the parent method.

     *

     * If we were free to assume that the host OS would always be 64-bits then the if condition in leftRotate could

     * be eliminated and we could knock this done to 0.60s.

     *

     * For comparison purposes, RC4 takes 0.16s and AES in CTR mode with the Eval engine takes 0.48s.

     * AES in CTR mode with the PHP engine takes 1.19s. Salsa20 / ChaCha20 do not benefit as much from the Eval

     * approach due to the fact that there are a lot less variables to de-reference, fewer loops to unroll, etc

     *

     * @param string $x

     */

    protected static function salsa20($x)

    {

        list(, $x0, $x1, $x2, $x3, $x4, $x5, $x6, $x7, $x8, $x9, $x10, $x11, $x12, $x13, $x14, $x15) = unpack('V*', $x);

        $z0 = $x0;

        $z1 = $x1;

        $z2 = $x2;

        $z3 = $x3;

        $z4 = $x4;

        $z5 = $x5;

        $z6 = $x6;

        $z7 = $x7;

        $z8 = $x8;

        $z9 = $x9;

        $z10 = $x10;

        $z11 = $x11;

        $z12 = $x12;

        $z13 = $x13;

        $z14 = $x14;

        $z15 = $x15;

        // @codingStandardsIgnoreStart

        // columnRound

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 16);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 12);

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 8);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 7);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 16);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 12);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 8);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 7);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 16);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 12);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 8);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 7);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 16);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 12);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 8);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 7);

        // rowRound

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 16);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 12);

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 8);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 7);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 16);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 12);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 8);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 7);

        $x2+= $x7; $x13 = self::leftRotate(intval($x13) ^ intval($x2), 16);

        $x8+= $x13; $x7 = self::leftRotate(intval($x7) ^ intval($x8), 12);

        $x2+= $x7; $x13 = self::leftRotate(intval($x13) ^ intval($x2), 8);

        $x8+= $x13; $x7 = self::leftRotate(intval($x7) ^ intval($x8), 7);

        $x3+= $x4; $x14 = self::leftRotate(intval($x14) ^ intval($x3), 16);

        $x9+= $x14; $x4 = self::leftRotate(intval($x4) ^ intval($x9), 12);

        $x3+= $x4; $x14 = self::leftRotate(intval($x14) ^ intval($x3), 8);

        $x9+= $x14; $x4 = self::leftRotate(intval($x4) ^ intval($x9), 7);

        // columnRound

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 16);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 12);

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 8);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 7);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 16);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 12);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 8);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 7);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 16);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 12);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 8);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 7);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 16);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 12);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 8);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 7);

        // rowRound

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 16);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 12);

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 8);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 7);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 16);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 12);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 8);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 7);

        $x2+= $x7; $x13 = self::leftRotate(intval($x13) ^ intval($x2), 16);

        $x8+= $x13; $x7 = self::leftRotate(intval($x7) ^ intval($x8), 12);

        $x2+= $x7; $x13 = self::leftRotate(intval($x13) ^ intval($x2), 8);

        $x8+= $x13; $x7 = self::leftRotate(intval($x7) ^ intval($x8), 7);

        $x3+= $x4; $x14 = self::leftRotate(intval($x14) ^ intval($x3), 16);

        $x9+= $x14; $x4 = self::leftRotate(intval($x4) ^ intval($x9), 12);

        $x3+= $x4; $x14 = self::leftRotate(intval($x14) ^ intval($x3), 8);

        $x9+= $x14; $x4 = self::leftRotate(intval($x4) ^ intval($x9), 7);

        // columnRound

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 16);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 12);

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 8);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 7);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 16);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 12);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 8);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 7);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 16);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 12);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 8);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 7);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 16);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 12);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 8);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 7);

        // rowRound

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 16);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 12);

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 8);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 7);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 16);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 12);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 8);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 7);

        $x2+= $x7; $x13 = self::leftRotate(intval($x13) ^ intval($x2), 16);

        $x8+= $x13; $x7 = self::leftRotate(intval($x7) ^ intval($x8), 12);

        $x2+= $x7; $x13 = self::leftRotate(intval($x13) ^ intval($x2), 8);

        $x8+= $x13; $x7 = self::leftRotate(intval($x7) ^ intval($x8), 7);

        $x3+= $x4; $x14 = self::leftRotate(intval($x14) ^ intval($x3), 16);

        $x9+= $x14; $x4 = self::leftRotate(intval($x4) ^ intval($x9), 12);

        $x3+= $x4; $x14 = self::leftRotate(intval($x14) ^ intval($x3), 8);

        $x9+= $x14; $x4 = self::leftRotate(intval($x4) ^ intval($x9), 7);

        // columnRound

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 16);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 12);

        $x0+= $x4; $x12 = self::leftRotate(intval($x12) ^ intval($x0), 8);

        $x8+= $x12; $x4 = self::leftRotate(intval($x4) ^ intval($x8), 7);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 16);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 12);

        $x1+= $x5; $x13 = self::leftRotate(intval($x13) ^ intval($x1), 8);

        $x9+= $x13; $x5 = self::leftRotate(intval($x5) ^ intval($x9), 7);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 16);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 12);

        $x2+= $x6; $x14 = self::leftRotate(intval($x14) ^ intval($x2), 8);

        $x10+= $x14; $x6 = self::leftRotate(intval($x6) ^ intval($x10), 7);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 16);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 12);

        $x3+= $x7; $x15 = self::leftRotate(intval($x15) ^ intval($x3), 8);

        $x11+= $x15; $x7 = self::leftRotate(intval($x7) ^ intval($x11), 7);

        // rowRound

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 16);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 12);

        $x0+= $x5; $x15 = self::leftRotate(intval($x15) ^ intval($x0), 8);

        $x10+= $x15; $x5 = self::leftRotate(intval($x5) ^ intval($x10), 7);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 16);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 12);

        $x1+= $x6; $x12 = self::leftRotate(intval($x12) ^ intval($x1), 8);

        $x11+= $x12; $x6 = self::leftRotate(intval($x6) ^ intval($x11), 7);