How to implement protection against multiple voting?

Question

PHP

Good afternoon.
Perhaps the question was asked earlier, but I'll ask:
Is it possible to protect against rating cheating by multiple voting? The rating is calculated by the "likes" of various social networks. networks and some users vote from several of them at once. In addition, there are unique ones / bots that vote from different accounts from the same computer.
I know about the ability to record the IP address of the voter, but will there be a problem in this case if several people sit behind NAT'om (or how can one explain a common external IP address)?

Answer 1

uniqueness of the voter in the web poll habrahabr.ru/qa/2726/
solution -> I suggest you read the article - javascript.ru/unsorted/id (@ habrahabr.ru/users/Dementor/ )

Answer 2

This is the whole point of Internet voting, if you don’t want cheating, do authorization using passports. All other methods are bypassed.

Answer 3

Generally speaking, no way.
1. Likes from social networks. Yes, then you can find and remove duplicates with pens or a script, but if you really want to, they will create fake accounts that only a person can distinguish, and even that is not a fact.
2. Cookies are cleared, ip often an office or a hostel with 2000 students can sit behind one ip.
3. You can enter mail, but also if you really want to, they will create hundreds of normal-looking postal addresses.
4. You can analyze the voting, see where the peaks come from, try to analyze the traffic.
But if a person wants to, he will vote for his candidate with a random frequency by changing ip, clearing cookies or creating fake email addresses/accounts in social networks.

Answer 4

Of course, reliable protection exists. But it is specific to each particular case.
In general, they usually use all the parameters in bulk: ip address, cookies, e-mail. Weed out those who like to vote several times.
In the event that you have a very important vote and you need to protect yourself from serious bots, it seems to me that the only option is to control your users. That is, only registered users can vote, and for example, they must be registered for some time already and have a certain activity for some time. If you came from a social network, you can enter similar criteria for an account on a social network.
Parameters (how long are registered, what activity is required) are selected individually for your case.
With this approach, the implementation of voting bots becomes too expensive and makes no sense.

Answer 5

In addition, you can set a cookie for the user

Answer 6

Recently, a competition was held just - only for SP did a restriction, naturally they wound up votes there. Well, the fact of cheating here is difficult to present.
IMHO, it is necessary to vote after authorization through social networks. with this option, it is much more difficult to wind.
however, it still won’t save you from human bots who will click from their accounts for 1-2 cents - there are such sites where such tasks are placed.

Answer 7

If the voting does not provide for the election of the President or a very large prize, SMS confirmation works quite well - either sending a code to the phone indicated by the voter, or sending SMS messages to the voters themselves. You can tie an SMS gate to a “long” number, you can also to a short one, there are many operators .