Simple and very fast encoder-decoder

Question

I will explain my need with an example;
www.domain.com/photo.jsp?id=23
here id is 23 and people can try every photo by incresing or decreasing the id number. I want to encode the id's while printing the id to screen as url and will decode everytime when i get the request from user.
So i need a very fast and simple logic of encode & decode. I have tested base64 at java but everyone knows the algortihm. Is there any other simple algorithm that i can generate on my own?
What do you advice to me except changing my database and search with hex keys?

Answer 1

believe me its strictly
needed on a photo web site... there are too much
reasons.I can't think of one.1)when ids are sequantial on db users can get the idea which after or before this photo is uploaded
2)when you see the normal integer numbers on ids you can remember it easily and edit the link by hand and see whats going on...
3)When u see user_id is=1 u can understand easily that he is an admin or one of the first member of website
4)when u try the maximum photo id or user id every user can understand how many user or photos are there in website
there are lots of things like above... They may be not that valueble for everyone but i think this have to be.