looking for simple PHP multi way encryption method

Question

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

Answer 1

This is the only basic built in function I know of.

$string = "/path/img.jpg";

$scramble = str_rot13($string);

echo "
Scrambled: ".$scramble;

echo "
Unscrambled: ".str_rot13($scramble);