looking for simple PHP multi way encryption method

[TatStaith]

I need to decrypt encrypted POST value strings with the aid of a secret static key.I have had a look into crypt() (but it's only one-way) and Mcrypt, GnuPG,... but I'm not happy with them. I think they are to complex for my simple issue. What should I use? I don't need IV shapes or super safe algorithms. Is there any basic PHP function, that I don't know yet?I just need to hide image pathes from users like that:ImageJPEG(ImageCreateFromJPEG( decode($_REQUEST['encryptedImage'],'secret Key') ));