And if you really want to do it yourself, i'd suggest you create a filname based on a md5 string, i would do it something like this:

...
package mdCrypt;
require Digest::MD5 qw(md5_hex);

sub createMD5 {
   my $self = shift;
   my ($string) = join (',',@_);
   return md5_hex($string);
}   
...

my $filename = $mdCryptObj->createMD5(localtime());
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