I have a regular request, for example:

```
http://myserver.com/index.php?var1=85842.23&var2=212.235&name=Teddie&valid=1

```

I would like those $\_GET parameters be encrypted to something like (not real, just an example:)):

```
http://myserver.com/index.php?eParam=ks883d48223v2czozoz227272j2nn2dn2d2du3dh4hn4f4f4f4h3383xh8383s38s3j83sj8s3j92h2s89hs387h2s87hs287h2s87h2ui2c3iuhc287z9m2389f

```

Of course, I need a built in key on each side, that will be able to decrypt that info. 
Is there any function that may render that possible ? 
I am not concerned about the client side, as it will be a running application, not a webpage or anything that would be easily reverse-engineered.

Thanks !