hi,
1) you need choice: either it is fast/short or complex and high security;
2) dilema: you need with encryption ideas and ask us - hehe, if I give you such idea on public (or even in private) than do you think will it still be realy secret? Do it yourself in dark room and not say to anyone; remember - if there are two man who know about a thing than the all know about it as well (=

Regards,
Oleg