Encrypting querystring

When using encrypted querystrings it seems pretty straightforward that the RECEIVING page just uses a function to decrypt the incoming querystring before the rest of the page is parsed.
Here's my question: on SENDING pages (e.g. using <FORM ACTION=""> or <A HREF=> or REDIRECT) is there a simple way to encrypt the querystrings before submitting the page, or does each instance of the querystrings have to call the encrypt function? In other words, I don't want to have to call the encrypt function for each instance of an ACTION, HREF, or REDIRECT which may be on a given sending page...
any ideas?

Could you provide an example of what your trying to do? I'm not really following you on tihs.