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Your Passwords Don't Suck — It's Your Policies
First time accepted submitter eGuy writes "ZDNet sparked a debate about password policies when John Fontana wrote about my open source (LGPL) password policy project that rewards XKCD-like passwords. Steve Watts of SecurEnvoy replies that it is too little, too late. What think ye? Is there hope for passwords?"
Every time a see a password like this "12ol3jkh!!asrdfw9g8" or "^TFGY78UH" I want to vomit. Why not make your password something like "This chicken tastes like shit!"
A white jacketed southern gentlemen's password is "This secret spice makes shit taste like chicken"
I got to the chocolate box before you, that's why the hard ones have teeth marks.
Any password policy that basically forces you to write down your password somewhere is broken. Sure, you can use a password vault but that's cumbersome for the various dozens of passwords strewn about the web and on mobile devices. But my biggest gripe is sites that lock you out (requiring a phone call) after 3 incorrect guesses. I could understand 100 incorrect guesses, but 3 guesses is not enough to recall a password when you have not used it in several months. One hundred guesses by a computer/hacker is nothing compared to the full password space.
...is why is it all so difficult to come up with some scheme to secure internet accessible resources. Corporate policy for me require password changes every 90 days and disallows any of the last eight passwords, and the use of letters and numbers. Effectively, I'm forced to write it down, negating all their efforts at obscurity. When will some bright CS geek invent a real solution to this problem. Is it that hard? Can't it be as simple as probing me for dynamic info that only I would know? How about visual methods- ask me who's in this picture of my co-workers or what is this family snapshot from my past, etc.?
Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?
Sure, its 28 characters, but its still lowercase only.
That makes it a lot weaker, no?
It makes it weaker by a factor of about 2^28.
Which sounds like a lot, but when the lowercase password space is already 26^28, it's not much.
XKCD's math is sound.
DRM: Terminator crops for your mind!
The main problem is indeed the policies. While I (mostly) agree with the main statements TFA makes, I have my own note to add:
.
My bank's website enforces a MAXIMUM length. I'd love to have a password like "c0rr3c7 h0r53 b4773ry st4p13", but I can't use more than 6 characters.
Yes, you read that right. 6 characters. Maximum.
I fear for my online bank info constantly
Why would there ever be a reason to enforce such a small maximum length? I don't get it.
Unlike porn, which yada yada rimshot hey-ooh!
Of course, your fiendishly clever non-standard spelling of et cetera would fool any such dictionary attacks.
Just because you're paranoid doesn't mean there isn't an invisible demon about to eat your face
Well, you can probably blame Little Bobby Tables for that. Depending on the programming language there are plenty of "control characters" in the ASCII 32-126 range, and it's much easier when deadlines are pressing to just restrict input to alphanumerics than try and sanitize against passwords that contain some variant of "'); drop table students;"
UNIX? They're not even circumcised! Savages!
The average adult that has been to University knows 20,000 head words. A head word is a group of words with essentially the same meaning. For example, expect, expectation, is expecting, etc are all one head word. 26^7 is a little bit over 8x10^9. If a user picks 4 headwords for their passphrase, the search space is 20000^4 or 1.6x10^17. And that's if we just use headwords. If the user uses variations the search space is rather huge.
You might say that 20,000 headwords includes a lot of strange vocabulary. But for instance, to get 95% vocabulary coverage in reading a newspaper you need just under 16,000 headwords. However, even if we restrict vocabulary to the most common 5,000 headwords (the average vocabulary of a 5 year old) we get a search space of 6.25x10^14.
XKCD style passphrases are dramatically more robust than a 7 character alphabetic password.
Congratulations on winning the Slashdot trifecta - you managed to invoke the GPL, cite XKCD, and slashvertise your own project all in one!
What part of "a well regulated militia" do you not understand?
No, it would be "weaker by half" if the alternative was a single capital letter at the beginning of the password.
In fact, the alternative is that any, some, or all of the 28 characters could be capitalized or not.
So the first character halves the password's strength if it is predictably lower-case.
and the second halves it again.
and so does the third.
Incidentally, halving or doubling the key space is not "a lot," not by any cryptologist's standards.
DRM: Terminator crops for your mind!
The only thing going for it is that you don't know that it's only lower case letters.
I think this is a very important point that lots of people overlook.
By prescribing the use of various character classes, you are actually weakening the password.
A proper password should allow the use of those classes, but not prescribe them.
When I was a kid, we had a game called "Mastermind". One person selected various coloured buttons and hid them behind a screen. The other person had to guess the colours / sequence.
We had various house rules about difficulty levels. One of the easiest ones was if they had to tell you the pattern. eg:
* double colour
* blank
etc
Same thing with passwords
Ever stop to think
My problem with the xkcd scheme is that users are lazy and rather than pick 4 random words, they'll pick 4 words that are easy to remember in sequence: "haveityourway" "darksideofthemoon" "thesearenothtedroidsyourelookingfor", so with a phrase dictionary and some grammar rules, you still have a good chance at brute-forcing some user's passwords.
You could perform this attack using Google's autocompletion database as a dictionary.
DRM: Terminator crops for your mind!
wait for the beta
rewriting history since 2109
All digital security boils down to the key sharing problem.
And the key sharing problem is "solved" in practice thusly:
Server: O hai! Give me your infos! Here's my certificate.
Computer: Warning! This certificate is not trusted!
User: Ignore warning, add certificate.
Computer: K.
OR
Server: O hai! Give me your infos! Here's my certificate.
Computer: This certificate is trusted because VeriSign totally vouches for these guys.
User: VeriSign?
Computer: Yeah yeah, we totally trust VeriSign. I mean, we've never met them, we don't know their policies, and we rely on VeriSign to tell us if their shit gets stolen, and we basically have no recourse if shit goes wrong, but we trust them.
User: K.
Nobody ever actually checks to see if something is legit because they want it to be painless and automatic. I'd love to be able to go to bank.com and view the certificate, then call the number on my credit card (or go in to an actual bank location) and see if the certificate matches up.
I use randomly-generated passwords (generated by reading /dev/random) that are at least 16 characters wrong. I restrict the character set to [A-Za-z0-9] which is a touch under 6 bits per characters, so I have about 95 bits of /dev/random-quality entropy.
The passwords are stored in a file encrypted with a long passphrase. The long passphrase is probably the weak link, but by not reusing passwords across different websites and using randomly-generated ones, I'm fairly well-protected if one of the sites I visit has its password file stolen.
The trouble with the pass phrase concept is that the whole words just become tokens. Most people's vocabulary is not that large.
That's why you use a standardized list of tokens (mostly words, but some non-word tokens as well) such as Diceware. With 7776 tokens, the keyspace is far larger than the "normal 7 character" password. The trick is to ensure that you are choosing the tokens randomly. You can use dice, your favorite random number generator, etc. I use several 4- and 5-token passphrases that I have remembered literally for years, each one unique. Type them enough times, and muscle memory takes care of the rest. Even after a period of non-use, it amazes me how my fingers will remember the passphrase but yet I can't recall the passphrase itself.
Most people's vocabulary is not that large.
Let's use the xkcd example: correct horse battery staple.
Using a list of the 5000 most commonly used words, I was able to find rankings for 3 of the 4 words:
"staple" doesn't even appear on the most common 5000 word list. But let's assume it did at 5000. That means your dictionary now is 5000 words large. 5000^4 = 6.25 * 10^14.
Now let's address your suggestion:
you don't really have a key space much larger than normal 7 character or so passwords offer
Now your average English keyboard has 47*2 = 94 type-able characters. 94^7 = 6.48477594 * 10^13. The xkcd example assuming it was smaller than it really was beat your suggestion by an order of magnitude.
Now let's address how large people's vocabularies are. According to wikipedia:
This translates into a wide range of vocabulary size by age five or six, at which time an English-speaking child will have learned about 2,500-5,000 words. An average student learns some 3,000 words per year, or approximately eight words per day.
But 6 year old kids don't have much interesting personal information that people are really after like credit cards. Let's read further:
A 1995 study estimated the vocabulary size of college-educated speakers at about 17,000 word families, and that of first-year college students (high-school educated) at about 12,000.
http://en.wikipedia.org/wiki/Vocabulary
So let's re-do the calculations with 10,000 words: 10 000^4 = 1.0 * 10^16.
Things will only get worse if you tell people to use numbers, names, special abbreviations, etc. For example it will be highly unlikely the following phrase will be in your dictionary: "5000 most common vocabulary". People can also use natural language and still fall way out of your dictionary: "yummy carne asada dinner". They can also use personal and vulgar language: "Stupid bitch Alice, never again".
The highly secure NSA and DoD password policy is very thorough, but one thing was left un-noticed about this policy. You can create a valid password by merely running your finder down a colum of the keyboard, and then holding down the shift key and doing the same thing. Really!!
To wit, this password is valid. Run your finger down the left-most column of your keyboard: 1qaz2wsx
Then hold down the SHIFT key and type !QAZ@WSX
Presto, you have a valid password that meets all the security requirements the NSA and DoD have imposed upon you.
Now that's okay for creating system images for deployment.
In 45 days when you need to change your password again, just shift to the next row of your keyboard. This will keep you okay for a couple of years or so until you run out of keyboard rows to use. Then, you just do it backwards. It really is that simple.
Try it!! It's almost unbelievable.
Kriston
Just did this:
Start with "awesomepasswordtoday"
1 year, 8 months
Go to "awesomepasswordtoday000"
7 centuries, 8 decades
Go to "000awesomepasswordtoday000"
less than 1 day
This tells me there is something in the logic that makes it a pretty unreliable metric of password strength.
Your password complexity requirements are worthless, users will pick easy to remember, insecure passwords no matter what the requirements are. They will, of course, literally fullfill the requirements. The difference is that you are much more likely to get user cooperation if password changes consisted of the computer picking 4 random words for them, rather than 12 random alphanumerics with a side dish of ASCII barf. The only reason users pick their own passwords for sensitive applications is that they'd write that shit down and stick it on the monitor (or under the keyboard, for the ones who "understand security") if you made it truly secure (i.e. generated it for them).
Right now your users pretend to pick secure passwords and you pretend that they do. You don't want to know how shitty they are, they don't want to tell you. As long as you don't find them on post-its and there is no visible compromise everyone is happy. Of course they should have PIN-secured, challenge-response based one time password generators, but let's face it, your systems just aren't important enough to secure them in a thoroughly user friendly manner. So if you actually do care beyond your users picking the simplest password that passes your requirements you very well might think about randomly generating 4 word passphrases for them, I think you even have some volunteers for a trial.
Analogies don't equal equalities, they are merely somewhat analogous.
Since when is coprophage rare? This is the Internet.
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