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NYU Group Says Its Scheme Makes Cracking Individual Passwords Impossible
An anonymous reader writes "Researchers at New York University have devised a new scheme called PolyPassHash for storing password hash data so that passwords cannot be individually cracked by an attacker. Instead of a password hash being stored directly in the database, the information is used to encode a share in a Shamir Secret Store (technical details PDF). This means that a password cannot be validated without recovering a threshold of shares, thus an attacker must crack groups of passwords together. The solution is fast, easy to implement (with C and Python implementations available), requires no changes to clients, and makes a huge difference in practice. To put the security difference into perspective, three random 6 character passwords that are stored using standard salted secure hashes can be cracked by a laptop in an hour. With a PolyPassHash store, it would take every computer on the planet longer to crack these passwords than the universe is estimated to exist. With this new technique, HoneyWords, and hardware solutions all available, does an organization have any excuse if their password database is disclosed and user passwords are cracked?."
Maybe I should look at this implementation for my upcoming MMO, which will likely go live somewhere in 2030 :)
...gis sdrawkcab (usually not responding to ACs; don't bother posting as AC)
Instantly, since all possible combinations will occur simultaneously.
Security isn't about safety. The vast majority of passwords are for identification, rather than security. And the ones that are for security, are for a "reasonable" amount of security. The biggest point is to make breaking it an obviously-intentional exercise -- because that can be made illegal. It's not about stopping criminals. It's about defining criminals.
So go ahead and make your twitter account password super-secure so that no one can ever hack in. And then go home to your cylinder lock, easily pickable, next to the big glass window. Then tell us how safe you are -- remembering that whether or not you keep your twitter password on a sticky note, and whether or not your desktop e-mail is accessible within your home without a password, your children and your wife, and your dog are sleeping behind not such password.
And any locksmith can break into any car, as a ten-second paid-for emergency service. And so can anyone who's watched them do it.
Stop trying to feel safe. Just feel safe. It's a lot easier, cheaper, and much more valid.
Did you leave your oven on?
To be useful, the system still needs to be able to tell whether a single user password is correct (and needs to do so reasonably efficiently). So if someone has a 6 character password (which is dumb) you can just try all possible passwords (there isn't that many possible 6 realistic character passwords). Either lots of them work (which would a problem) or you found the password.
No, as I understand it from the article, you can't tell if a single user password is correct, because you don't have a measure for "correct"-- all that you check whether that password points to the same place (in a multidimensional phase space) that other passwords project to. (It does seems to only work is you can assuming that all, or at least "most," of the other passwords people enter are correct).
http://www.geoffreylandis.com
So it turns out their system, after a reboot, can't just validate a single user (I guess that was a crazy assumption on my part) - it has to have logins from a number of users before it can authenticate anyone. And if you don't want the system breakable by someone just creating a bunch of accounts (eg. normal users on a public website), these prime logins have to be more "special accounts".
Practically, if you need some special logins after every reboot in order for the system to come online, you're going to have to have multiple people assigned this job. Or one person with N passwords he logs in with. In which case, why not just give that guy a one time pad sort of thing that he primes each server with? I mean, these passwords are going to be unrecoverable and encrypted with, effectively, an unchanging key. So... uh, we have ways to do that.
Oh wait, there's an extension that gets around this, and has the property of "the server can check and eliminate most wrong passwords right after reboot". I'm sure a lot of bosses will like that - it'll reject most wrong passwords. Great.
It's a clever idea, but I think there's some real hard sell problems there.
Let's not stir that bag of worms...
I call it, "Monkey Improbability Hacking".
.0000024 btc
I'll lease it to you for the low low price of
I am Bennett Haselton! I am Bennett Haselton!
No, it doesn't work that way; that's the whole point. If you have the hash and are trying to compare against it, you can't just try all the possible passwords because if haven't cracked the other passwords you don't know how to produce the hash that corresponds to a given password. If you're just trying passwords at a login prompt, brute force is trivial to defeat (best method will most likely be simply imposing an increasing login delay with each wrong attempt).
...it would take every computer on the planet longer to crack these passwords than the universe is estimated to exist.
Let's hope they're not creationists.
That problem is already solved. It is called SRP With SRP, even if the attacker has full access to the host, they cannot reverse engineer the passphrase.
Yes, did you RTFA? They specifically mention that this step is needed everytime the system boots. They have also provided some ideas on how to achieve this automatically.
Even if all of them typed the same thing the rest of them would type the other combinations.
Did you leave your oven on?
You bastard. Did you have to do that?
More music, fewer hits
Get them to write their passwords on a post-it(tm) note and stick it to the server.
Do I have to do all the thinking around here?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Does it come with an actual monkey? I wouldn't want to end up with an MSCE or some other poor substitute, monkeys are both cuter and put less shit on your servers. Of course both could be replaced by a very small shell script. but I need one for the head count and scripts run headless so that won't do.
Live today, because you never know what tomorrow brings
That was a flaw with early experiments, but we've since worked it out. With our updated business model, we only provide you with one monkey and typewriter in this universe. At the same time, in each of infinite parallel universes, the parallel 'we' give the parallel 'you' a monkey and typewriter as well. Each typewriter is equipped with a lovingly crafted and painstakingly entangled transceiver to broadcast and monitor an infinity of random typing, listening and waiting for your answer to ephemerally cross its antenna.
Great news! It's statistically certain that one of the infinite monkeys has already typed the answer you seek. However, due to information propagation delays, it may take between zero and infinite time to reach your universe. Rest assured, though, it's on its way. While you wait, please enjoy your monkey. And typewriter.
Thank you for your business!
How can I believe you when you tell me what I don't want to hear?