I just realized you had the same idea. But
1. The sum of two strings can be identical, try "rolf" and "rofl" and "flor"
2. for ( < @array > ) is dangerous nonsense, always do for ( @array ) without glob
3. if you wanna play save, try a system cmd to get a mac adress.
4. You could determine a unique seed at installation time and store it in a module MyProject::Seed you use later. Like this you have full control (just edit the module) and you only need to fiddle once with the OS for a unique key.
5. you could even request a unique key over web at installation time.
In reply to Re^4: How do I make a random shuffle deterministic?