CourseSmart Decryption Routine

coursesmart_decrypt.as

var _local20:uint;
var _local21:uint;
var _local22:uint;
var _local23:uint;
var _local24:uint;
var _local25:uint;
var _local26:uint;
var _local27:uint;

var _local4:ByteArray = new ByteArray();
var _local10:uint = _arg2.readUnsignedByte(); 
var _local7:uint = _arg2.readUnsignedByte(); 
var _local8:uint = _arg2.readUnsignedByte(); 
var _local6:Array = new Array();
var _local5:Array = new Array();

var _local9:int = 0;
while (_local9 < _local10) {
    _local6.push(_arg2.readUnsignedByte());
    _local9++;
};
_local9 = 0;
while (_local9 < _local8) {
    _local5.push(_arg2.readUnsignedByte());
    _local9++;
};
var _local11:uint = _arg2.position;
var _local12:uint = (_arg2.length - _local11);
var _local13:int = (_local12 / _local7);
var _local14:int = (_local12 - (_local13 * (_local7 - 1)));
var _local15:int;
while (_local15 < _local12) {
    _local20 = (_arg2.readUnsignedByte() ^ _local6[(_local15 % _local6.length)]);
    _local4.writeByte(_local20);
    _local15++;
};
_arg2.clear();
var _local16:ByteArray = new ByteArray();
var _local17:ByteArray = new ByteArray();
var _local18:uint = _local8;
while (_local18 > 0) {
    _local21 = (_local18 - 1);
    _local22 = _local5[_local21];
    if (_local22 == _local21){
    } else {
        _local23 = ((_local22)==(_local7 - 1)) ? _local14 : _local13;
        _local24 = (_local22 * _local13);
        _local25 = (_local21 * _local13);
        _local26 = ((_local21)==(_local7 - 1)) ? _local14 : _local13;
        _local27 = Math.min(_local23, _local26);
        _local4.position = _local25;
        _local16.position = 0;
        _local4.readBytes(_local16, 0, _local27);
        _local4.position = _local24;
        _local4.readBytes(_local17, 0, _local27);
        _local4.position = _local25;
        _local4.writeBytes(_local17, 0, _local27);
        _local4.position = _local24;
        _local4.writeBytes(_local16, 0, _local27);
    };
    _local18--;
};
_local4.position = 0;
_local16.clear();
_local17.clear();