I whould like to know in what encryption should I encode my data and why

first of all, I use GET method because it is search engine inside webside.

second, I use RTL language (hebrew)

and thrid which basiclly is why I ask this question - firefox and safari (as I understood) encode and decode urls automaticly so if I encoded url, in firefox I will see it decoded which is good but if I copy-paste the url to the address bar and than enter the site firefox encode the uncoded url to utf (i think).

anyway, what en/decode should I use, and how can I overcome the firefox auto en/decode?