Programming a simple signature function?

I have a simple programming problem. I have several tables of numbers (in Excel) and I need to distinguish them from each other mathematically with a simple "digital sigature" type number. I don't really need a digital sig, but I do need some way of reducing the entire table to a simple number and using that number as an ID to distinguish it from another table.

My real tables are 100 rows long, but lets use a simple example of 5 rows: If Table A is the numbers [1, 2, 3, 4, 5] and table B is [2, 1, 3, 4, 5]. Then I need a way to come up with a single number that will be uniquely different for each table - so that is the positions of the numbers change, their "ID" signature will change as well. I can't use a simple sum, because obviously these would sum to the same number.

This is a lot like getting a digital signature - but that is beyond my programming ability. But with a signature, if any number changes anywhere, the whole signature is different.

Any ideas?