ParagonIE_Sodium_Core_AES::keySchedule( string $key ): ParagonIE_Sodium_Core_AES_KeySchedule

250    public static function keySchedule($key)251    {252        $key_len = self::strlen($key);253        switch ($key_len) {254            case 16:255                $num_rounds = 10;256                break;257            case 24:258                $num_rounds = 12;259                break;260            case 32:261                $num_rounds = 14;262                break;263            default:264                throw new SodiumException('Invalid key length: ' . $key_len);265        }266        $skey = array();267        $comp_skey = array();268        $nk = $key_len >> 2;269        $nkf = ($num_rounds + 1) << 2;270        $tmp = 0;271 272        for ($i = 0; $i < $nk; ++$i) {273            $tmp = self::load_4(self::substr($key, $i << 2, 4));274            $skey[($i << 1)] = $tmp;275            $skey[($i << 1) + 1] = $tmp;276        }277 278        for ($i = $nk, $j = 0, $k = 0; $i < $nkf; ++$i) {279            if ($j === 0) {280                $tmp = (($tmp & 0xff) << 24) | ($tmp >> 8);281                $tmp = (self::subWord($tmp) ^ self::$Rcon[$k]) & self::U32_MAX;282            } elseif ($nk > 6 && $j === 4) {283                $tmp = self::subWord($tmp);284            }285            $tmp ^= $skey[($i - $nk) << 1];286            $skey[($i << 1)] = $tmp & self::U32_MAX;287            $skey[($i << 1) + 1] = $tmp & self::U32_MAX;288            if (++$j === $nk) {289                /** @psalm-suppress LoopInvalidation */290                $j = 0;291                ++$k;292            }293        }294        for ($i = 0; $i < $nkf; $i += 4) {295            $q = ParagonIE_Sodium_Core_AES_Block::fromArray(296                array_slice($skey, $i << 1, 8)297            );298            $q->orthogonalize();299            // We have to overwrite $skey since we're not using C pointers like BearSSL did300            for ($j = 0; $j < 8; ++$j) {301                $skey[($i << 1) + $j] = $q[$j];302            }303        }304        for ($i = 0, $j = 0; $i < $nkf; ++$i, $j += 2) {305            $comp_skey[$i] = ($skey[$j] & 0x55555555)306                | ($skey[$j + 1] & 0xAAAAAAAA);307        }308        return new ParagonIE_Sodium_Core_AES_KeySchedule($comp_skey, $num_rounds);309    }