memzero example

/** @var string The first block of the chacha20 keystream, used as a poly1305 key */
        $block0 = ParagonIE_Sodium_Core_ChaCha20::stream(
            32,
            $nonce,
            $key
        );

        /* Recalculate the Poly1305 authentication tag (MAC): */
        $state = new ParagonIE_Sodium_Core_Poly1305_State($block0);
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
        } catch (SodiumException $ex) {
            $block0 = null;
        }
        $state->update($ad);
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($adlen));
        $state->update($ciphertext);
        $state->update(ParagonIE_Sodium_Core_Util::store64_le($clen));
        $computed_mac = $state->finish();

        /* Compare the given MAC with the recalculated MAC: */
        if (!ParagonIE_Sodium_Core_Util::verify_16($computed_mac, $mac)) {
            

            $len -= 64;
        }
        if ($len > 0) {
            $c .= self::substr(
                self::core_salsa20($in, $kcopy, null),
                0,
                $len
            );
        }
        try {
            ParagonIE_Sodium_Compat::memzero($kcopy);
        } catch (SodiumException $ex) {
            $kcopy = null;
        }
        return $c;
    }

    /** * @internal You should not use this directly from another application * * @param string $m * @param string $n * @param int $ic * @param string $k * @return string * @throws SodiumException * @throws TypeError */

/** @var resource $ofp */
        $ofp = fopen($outputFile, 'wb');
        if (!is_resource($ofp)) {
            fclose($ifp);
            throw new SodiumException('Could not open output file for writing');
        }

        $res = self::box_decrypt($ifp, $ofp, $size, $nonce, $keypair);
        fclose($ifp);
        fclose($ofp);
        try {
            ParagonIE_Sodium_Compat::memzero($nonce);
            ParagonIE_Sodium_Compat::memzero($ephKeypair);
        } catch (SodiumException $ex) {
            if (isset($ephKeypair)) {
                unset($ephKeypair);
            }
        }
        return $res;
    }

    /** * Seal a file (rather than a string). Uses less memory than * ParagonIE_Sodium_Compat::crypto_box_seal(), but produces * the same result. * * @param string $inputFile Absolute path to a file on the filesystem * @param string $outputFile Absolute path to a file on the filesystem * @param string $publicKey ECDH public key * * @return bool * @throws SodiumException * @throws TypeError */

hash_update($hs, self::substr($pk, 0, 32));
        hash_update($hs, $message);
        $hramHash = hash_final($hs, true);

        # sc_reduce(hram);         # sc_muladd(sig + 32, hram, az, nonce);         $hram = self::sc_reduce($hramHash);
        $sigAfter = self::sc_muladd($hram, $az, $nonce);
        $sig = self::substr($sig, 0, 32) . self::substr($sigAfter, 0, 32);

        try {
            ParagonIE_Sodium_Compat::memzero($az);
        } catch (SodiumException $ex) {
            $az = null;
        }
        return $sig;
    }

    /** * @internal You should not use this directly from another application * * @param string $sig * @param string $message * @param string $pk * @return bool * @throws SodiumException * @throws TypeError */

    function memzero(&$str)
    {
        ParagonIE_Sodium_Compat::memzero($str);
    }
}
if (!is_callable('\\Sodium\\randombytes_buf')) {
    /** * @see ParagonIE_Sodium_Compat::randombytes_buf() * @param int $amount * @return string * @throws \TypeError */
    function randombytes_buf($amount)
    {
        

self::hash_update($hs, self::substr($pk, 0, 32));
        self::hash_update($hs, $message);
        $hramHash = hash_final($hs, true);

        # sc_reduce(hram);         # sc_muladd(sig + 32, hram, az, nonce);         $hram = self::sc_reduce($hramHash);
        $sigAfter = self::sc_muladd($hram, $az, $nonce);
        $sig = self::substr($sig, 0, 32) . self::substr($sigAfter, 0, 32);

        try {
            ParagonIE_Sodium_Compat::memzero($az);
        } catch (SodiumException $ex) {
            $az = null;
        }
        return $sig;
    }

    /** * @internal You should not use this directly from another application * * @param string $sig * @param string $message * @param string $pk * @return bool * @throws SodiumException * @throws TypeError */

            $len -= 64;
        }
        if ($len > 0) {
            $c .= self::substr(
                self::core_salsa20($in, $kcopy, null),
                0,
                $len
            );
        }
        try {
            ParagonIE_Sodium_Compat::memzero($kcopy);
        } catch (SodiumException $ex) {
            $kcopy = null;
        }
        return $c;
    }

    /** * @internal You should not use this directly from another application * * @param string $m * @param string $n * @param int $ic * @param string $k * @return string * @throws SodiumException * @throws TypeError */

ParagonIE_Sodium_Core_Util::declareScalarType($length, 'int', 2);

        if (self::useNewSodiumAPI()) {
            return sodium_crypto_generichash_final($ctx, $length);
        }
        if (self::use_fallback('crypto_generichash_final')) {
            $func = '\\Sodium\\crypto_generichash_final';
            return (string) $func($ctx, $length);
        }
        if ($length < 1) {
            try {
                self::memzero($ctx);
            } catch (SodiumException $ex) {
                unset($ctx);
            }
            return '';
        }
        if (PHP_INT_SIZE === 4) {
            $result = ParagonIE_Sodium_Crypto32::generichash_final($ctx, $length);
        } else {
            $result = ParagonIE_Sodium_Crypto::generichash_final($ctx, $length);
        }
        try {
            

/** @var string The first block of the chacha20 keystream, used as a poly1305 key */
        $block0 = ParagonIE_Sodium_Core32_ChaCha20::stream(
            32,
            $nonce,
            $key
        );

        /* Recalculate the Poly1305 authentication tag (MAC): */
        $state = new ParagonIE_Sodium_Core32_Poly1305_State($block0);
        try {
            ParagonIE_Sodium_Compat::memzero($block0);
        } catch (SodiumException $ex) {
            $block0 = null;
        }
        $state->update($ad);
        $state->update(ParagonIE_Sodium_Core32_Util::store64_le($adlen));
        $state->update($ciphertext);
        $state->update(ParagonIE_Sodium_Core32_Util::store64_le($clen));
        $computed_mac = $state->finish();

        /* Compare the given MAC with the recalculated MAC: */
        if (!ParagonIE_Sodium_Core32_Util::verify_16($computed_mac, $mac)) {
            

/** * @see ParagonIE_Sodium_Compat::memzero() * @param string $string * @return void * @throws SodiumException * @throws TypeError * * @psalm-suppress ReferenceConstraintViolation */
    function sodium_memzero(&$string)
    {
        ParagonIE_Sodium_Compat::memzero($string);
    }
}
if (!is_callable('sodium_pad')) {
    /** * @see ParagonIE_Sodium_Compat::pad() * @param string $unpadded * @param int $block_size * @return string * @throws SodiumException * @throws TypeError */