GPG_Utility::pack_octets PHP Méthode

    static function pack_octets($octets)
    {
        $i = 0;
        $j = 0;
        $len = count($octets);
        $b = array_fill(0, $len / 4, 0);
        if (!$octets || $len % 4) {
            return;
        }
        for ($i = 0, $j = 0; $j < $len; $j += 4) {
            $b[$i++] = $octets[$j] | $octets[$j + 1] << 0x8 | $octets[$j + 2] << 0x10 | $octets[$j + 3] << 0x18;
        }
        return $b;
    }

 static function encrypt($block, $ctx)
 {
     $RCON = GPG_Cipher::$RCON;
     $S = GPG_Cipher::$S;
     $T1 = GPG_Cipher::$T1;
     $T2 = GPG_Cipher::$T2;
     $T3 = GPG_Cipher::$T3;
     $T4 = GPG_Cipher::$T4;
     $r = 0;
     $t0 = 0;
     $t1 = 0;
     $t2 = 0;
     $t3 = 0;
     $b = GPG_Utility::pack_octets($block);
     $rounds = $ctx->rounds;
     $b0 = $b[0];
     $b1 = $b[1];
     $b2 = $b[2];
     $b3 = $b[3];
     for ($r = 0; $r < $rounds - 1; $r++) {
         $t0 = $b0 ^ $ctx->rk[$r][0];
         $t1 = $b1 ^ $ctx->rk[$r][1];
         $t2 = $b2 ^ $ctx->rk[$r][2];
         $t3 = $b3 ^ $ctx->rk[$r][3];
         $b0 = $T1[$t0 & 255] ^ $T2[$t1 >> 8 & 255] ^ $T3[$t2 >> 16 & 255] ^ $T4[GPG_Utility::zshift($t3, 24)];
         $b1 = $T1[$t1 & 255] ^ $T2[$t2 >> 8 & 255] ^ $T3[$t3 >> 16 & 255] ^ $T4[GPG_Utility::zshift($t0, 24)];
         $b2 = $T1[$t2 & 255] ^ $T2[$t3 >> 8 & 255] ^ $T3[$t0 >> 16 & 255] ^ $T4[GPG_Utility::zshift($t1, 24)];
         $b3 = $T1[$t3 & 255] ^ $T2[$t0 >> 8 & 255] ^ $T3[$t1 >> 16 & 255] ^ $T4[GPG_Utility::zshift($t2, 24)];
     }
     $r = $rounds - 1;
     $t0 = $b0 ^ $ctx->rk[$r][0];
     $t1 = $b1 ^ $ctx->rk[$r][1];
     $t2 = $b2 ^ $ctx->rk[$r][2];
     $t3 = $b3 ^ $ctx->rk[$r][3];
     $b[0] = GPG_Cipher::F1($t0, $t1, $t2, $t3) ^ $ctx->rk[$rounds][0];
     $b[1] = GPG_Cipher::F1($t1, $t2, $t3, $t0) ^ $ctx->rk[$rounds][1];
     $b[2] = GPG_Cipher::F1($t2, $t3, $t0, $t1) ^ $ctx->rk[$rounds][2];
     $b[3] = GPG_Cipher::F1($t3, $t0, $t1, $t2) ^ $ctx->rk[$rounds][3];
     return GPG_Utility::unpack_octets($b);
 }