For my computer security course we are brainstorming different ways to use attributes for a unique user (that are readily available over a network) to prevent various mischievous activities. We've already investigated clustering email attributes to help reduce spam and possibly locate botnets, along with some other things. We were asked about validating unique votes for internet contests today, and I'm really stumped. Here are the conditions:
A website is running a week-long contest where users are allowed to vote once per day. There are no accounts or logins necessary to vote, all you need to supply is a valid email address. No verification emails are sent. What can you do to maintain the integrity of the contest?
-I was thinking about tracking IPs, but many computers can be a part of a single network. Is there anything more specific than an IP that is unique to each computer, that is also accessible over a network?
-Also, how can you stop people from entering multiple valid personal email addresses (for example, I have a spam email address that I give out at stores, a university email address, and then an old one I don't use, but they are all valid!).
-Could the contest be illegitimately won by someone who is IP spoofing?
I've seen some similar questions asked on here, but they all contain very complex procedures to minimize cheating. This one is very simple, and there are obviously many holes present.