ParagonIE_Sodium_Core_AES_KeySchedule

10class ParagonIE_Sodium_Core_AES_KeySchedule11{12    /** @var array<int, int> $skey -- has size 120 */13    protected $skey;14 15    /** @var bool $expanded */16    protected $expanded = false;17 18    /** @var int $numRounds */19    private $numRounds;20 21    /**22     * @param array $skey23     * @param int $numRounds24     */25    public function __construct(array $skey, $numRounds = 10)26    {27        $this->skey = $skey;28        $this->numRounds = $numRounds;29    }30 31    /**32     * Get a value at an arbitrary index. Mostly used for unit testing.33     *34     * @param int $i35     * @return int36     */37    public function get($i)38    {39        return $this->skey[$i];40    }41 42    /**43     * @return int44     */45    public function getNumRounds()46    {47        return $this->numRounds;48    }49 50    /**51     * @param int $offset52     * @return ParagonIE_Sodium_Core_AES_Block53     */54    public function getRoundKey($offset)55    {56        return ParagonIE_Sodium_Core_AES_Block::fromArray(57            array_slice($this->skey, $offset, 8)58        );59    }60 61    /**62     * Return an expanded key schedule63     *64     * @return ParagonIE_Sodium_Core_AES_Expanded65     */66    public function expand()67    {68        $exp = new ParagonIE_Sodium_Core_AES_Expanded(69            array_fill(0, 120, 0),70            $this->numRounds71        );72        $n = ($exp->numRounds + 1) << 2;73        for ($u = 0, $v = 0; $u < $n; ++$u, $v += 2) {74            $x = $y = $this->skey[$u];75            $x &= 0x55555555;76            $exp->skey[$v] = ($x | ($x << 1)) & ParagonIE_Sodium_Core_Util::U32_MAX;77            $y &= 0xAAAAAAAA;78            $exp->skey[$v + 1] = ($y | ($y >> 1)) & ParagonIE_Sodium_Core_Util::U32_MAX;79        }80        return $exp;81    }82}