hashEquals example

    public static function auth_verify($mac, $message, $key)
    {
        return ParagonIE_Sodium_Core_Util::hashEquals(
            $mac,
            self::auth($message, $key)
        );
    }

    /** * X25519 key exchange followed by XSalsa20Poly1305 symmetric encryption * * @internal Do not use this directly. Use ParagonIE_Sodium_Compat. * * @param string $plaintext * @param string $nonce * @param string $keypair * @return string * @throws SodiumException * @throws TypeError */

    public static function auth_verify($mac, $message, $key)
    {
        return ParagonIE_Sodium_Core32_Util::hashEquals(
            $mac,
            self::auth($message, $key)
        );
    }

    /** * X25519 key exchange followed by XSalsa20Poly1305 symmetric encryption * * @internal Do not use this directly. Use ParagonIE_Sodium_Compat. * * @param string $plaintext * @param string $nonce * @param string $keypair * @return string * @throws SodiumException * @throws TypeError */

/** * @internal You should not use this directly from another application * * @param string $left * @param string $right * @return int * @throws SodiumException * @throws TypeError */
    public static function memcmp($left, $right)
    {
        if (self::hashEquals($left, $right)) {
            return 0;
        }
        return -1;
    }

    /** * Multiply two integers in constant-time * * Micro-architecture timing side-channels caused by how your CPU * implements multiplication are best prevented by never using the * multiplication operators and ensuring that our code always takes * the same number of operations to complete, regardless of the values * of $a and $b. * * @internal You should not use this directly from another application * * @param int $a * @param int $b * @param int $size Limits the number of operations (useful for small, * constant operands) * @return int */

        $pieces = explode('$', (string) $hash);
        $prefix = implode('$', array_slice($pieces, 0, 4));

        // Rebuild the expected header.         /** @var int $ops */
        $ops = (int) $opslimit;
        /** @var int $mem */
        $mem = (int) $memlimit >> 10;
        $encoded = self::CRYPTO_PWHASH_STRPREFIX . 'v=19$m=' . $mem . ',t=' . $ops . ',p=1';

        // Do they match? If so, we don't need to rehash, so return false.         return !ParagonIE_Sodium_Core_Util::hashEquals($encoded, $prefix);
    }

    /** * @param string $passwd * @param string $hash * @return bool * @throws SodiumException * @throws TypeError * @psalm-suppress MixedArgument */
    public static function crypto_pwhash_str_verify($passwd, $hash)
    {