crypt() is very similar to Linux passwords. I would use MD5 (better hash) or Crypt::Blowfish (reversible if you want to be able to email password reminders) but this is very simple to implement:

my $salt = 'Na';
print crypt( 'password', $salt ), $/;
print "Valid" if crypt( 'password', $salt ) eq 'Na3eD25AE5/zI';
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