# ** Note ** This is intended to be unique, not unguessable. 
    my $id = MD5->hexhash(MD5->hexhash(time.{}.rand().$$)); 
    $id =~ tr|+/=|-_.|;     # make non-word characters URL friendly
[download]

Uh, that tr never fires there. hexhash always generates hex chars. Perhaps you're confusing this with the base64 versions that I was trying to steer the other petitioner around.

-- Randal L. Schwartz, Perl hacker