Identical Bots?

[space.invaders]

Would some organizer please have a look at these participants, they seem to have identical bots.

http://ai-contest.com/profile.php?user_id=8962
http://ai-contest.com/profile.php?user_id=8525
http://ai-contest.com/profile.php?user_id=8561

If they play against each other they draw with identical, non-trivial moves:
http://ai-contest.com/visualizer.php?game_id=8459817
http://ai-contest.com/visualizer.php?game_id=8439316

and their last submissions are all from Oct 24 within 18 minutes.

If their bots are identical indeed, perhaps you can inform them that this is against the rules. Doesn't look like they wanted to violate the rules on purpose, because then it would certainly have been done more cleverly. Would be a pity to exclude them from the competition, because their bot is actually quite good.

[amstan]

Yeah, this is uncool.
It's identical passwords, different email addresses.

[jeff.cameron]

We detect duplicate accounts fairly often, and we will definitely follow the normal procedure with these ones.

It's probably worth mentioning that we don't actually store people's passwords in the database. amstan is able to tell that these accounts all have the same password because the cryptographic hashes of the passwords (which we do store) are the same. Your data is safe, and we are not evil!

[RebelXT]

It's good to hear rule violations will not be tolerated. This person is most likely testing multiple nearly identical versions of the bot on the official server. That's what TCP server is for.

[dimkadimon]

These also look identical. It is so sad that these are high-ranking bots.

http://www.ai-contest.com/visualizer.ph ... id=8488650

[jonoff]

[spz]

If the salt remains the same, then the hash remains the same: salt+password = salt+password.

Unless you use a different salt per user, like their username, since it cannot change.

In short, salt could be used but for the same passwords the hash would still be the same, which isn't really that big of a problem

[Terr]

You're supposed to salt per-user.

Salting per-system is not very effective since (especially in a system with a great many accounts) an attacker can still generate a per-system rainbow table and come out ahead.

[jonoff]

[spz]