<?php
/** @package    php-gpg::GPG */

/** require supporting files */
require_once("Cipher.php");

/**
 * @package    php-gpg::GPG
 */
class Expanded_Key {
    var $rounds;
    var $rk;

	function Expanded_Key($key) {
        $RCON = GPG_Cipher::$RCON;
        $S = GPG_Cipher::$S;

		$maxkc = GPG_Cipher::$maxkc;
		$maxrk = GPG_Cipher::$maxrk;

        $kc = 0;
        $i = 0;
        $j = 0;
        $r = 0;
        $t = 0;
        $rounds = 0;
        $keySched = array_fill(0, $maxrk + 1, 0);
        $keylen = strlen($key);
        $k = array_fill(0, $maxkc, 0);
        $tk = array_fill(0, $maxkc, 0);
        $rconpointer = 0;

        if ($keylen == 16) {
            $rounds = 10;
            $kc = 4;
        } else if ($keylen == 24) {
            $rounds = 12;
            $kc = 6;
        } else if ($keylen == 32) {
            $rounds = 14;
            $kc = 8;
        } else {
            return;
        }

        for($i = 0; $i < $maxrk + 1; $i++) $keySched[$i] = array_fill(0, 4, 0);
        for($i = 0, $j = 0; $j < $keylen; $j++, $i += 4) {
                if ($i < $keylen) {
                    $k[$j] = ord($key[$i]) | (ord($key[$i + 1]) << 0x8) |
                        (ord($key[$i + 2]) << 0x10) | (ord($key[$i + 3]) << 0x18);
                } else {
                    $k[$j] = 0;
                }
        }
        for($j = $kc - 1; $j >= 0; $j--) $tk[$j] = $k[$j];

        $r = 0;
        $t = 0;
        for($j = 0; ($j < $kc) && ($r < $rounds + 1); ) {
            for(; ($j < $kc) && ($t < 4); $j++, $t++) {
                $keySched[$r][$t] = $tk[$j];
            }
            if($t == 4) {
                $r++;
                $t = 0;
            }
        }

        while($r < $rounds + 1) {
            $temp = $tk[$kc - 1];

			$tk[0] ^= $S[GPG_Utility::B1($temp)] | ($S[GPG_Utility::B2($temp)] << 0x8) |
				($S[GPG_Utility::B3($temp)] << 0x10) | ($S[GPG_Utility::B0($temp)] << 0x18);
            $tk[0] ^= $RCON[$rconpointer++];

            if ($kc != 8) {
                for($j = 1; $j < $kc; $j++) $tk[$j] ^= $tk[$j - 1];
            } else {
                for($j = 1; $j < $kc / 2; $j++) $tk[$j] ^= $tk[$j - 1];
 
                $temp = $tk[$kc / 2 - 1];
				$tk[$kc / 2] ^= $S[GPG_Utility::B0($temp)] | ($S[GPG_Utility::B1($temp)] << 0x8) |
					($S[GPG_Utility::B2($temp)] << 0x10) | ($S[GPG_Utility::B3($temp)] << 0x18);

                for($j = $kc / 2 + 1; $j < $kc; $j++) $tk[$j] ^= $tk[$j - 1];
            }

            for($j = 0; ($j < $kc) && ($r < $rounds + 1); ) {
                for(; ($j < $kc) && ($t < 4); $j++, $t++) {
                    $keySched[$r][$t] = $tk[$j];
                }
                if($t == 4) {
                    $r++;
                    $t = 0;
                }
            }
        }
    
        $this->rounds = $rounds;
        $this->rk = $keySched;
        return $this;
    }
}

?>