encrypt passwords on URL

HI This is a sort-of continuation on my previous question regarding being able to "puch" a file to a client machine using PHP. I have created a login page that connects to the ftp server and then lists the contents of the folder. My original hope was that I could somehow have the user just click on the file he want's to download it, but since the files are not in a webfolder, I couldn't just make links to them... Another scenraio that could work is to simply have the user go to ftp://username:password@servername.com BUT, that leaves the password on the URL and the data is sensitive. So, my question: Can I encrypt the password with PHP and then generate the link as above but with the encrypted password?