Once you see them as tokens that 3rd parties will probably lose, then you know our efforts should be in secure token management software (keepass, lastpass, 1password, etc).
Maybe the problem is that we have it backwards. Maybe it shouldn't be something you remember and push to the authentication mechanism, but something that the authentication mechanism pushes to you.
Like, what if you pick the corpus of a novel that you've read as your master password. And the password manager uses that novel plus several other novels that you have selected (but didn't read/won't read?) to give you a series of multiple choice selections to determine if you know the right book. Just a few short passages. Preferably with proper nouns stripped out.
You have to select the passages from the correct book for all the multiple choices. That way rather than recall, the memory factor is recognition. Combine it with a non-memorable token which you have to present first in order to even see the recognition factor test and you might have something workable.
I didn't say to use it by itself. I said that your OTP would be required first to even access it. And of course you could provide backoff. And then you'd also have to be answering a series of multiple choice questions all correctly.
I dunno, just a thought, but do you get what I'm saying about recognition vs recall? Why don't we have the computer test us about things we're good at if part of the test has to be something only our individual brain is capable of?
You've just redefined memorable to make the problem disappear. That's not terrible useful. The idea is not to come up with a perfect solution that virtually no one will use.
Passwords, which are easy to remember, are not random and not strong. If I will know that your passwords are 3 dictionary words, I will try to bruteforce them using words, not characters. 50000 common words in ^3 is too small.
Jut generate random password and memorize it, like you memorize other random numbers and strings, like lock combinations, room numbers, car numbers, etc. Learn how to memorize arbitrary long strings of characters and you will have no problems with them for rest of your life.
To make life easier, memorize short password first, e.g. Gc@b%, let call it "alpha", then, when password expired, memorize two new short passwords, "beta" and "gamma", and include your old password "alpha" between them (or rotate it, or flip, or use part of it, etc.), so your password will 2 times longer and stronger. Repeat procedure next time. In short time, you will have list of "words" - short pieces of random strings, which are hard to guess by strangers, but remembered well by you. You can use that dictionary to construct new passwords while keeping adding new random or non-random "words" to dictionary, e.g. "car" - something related to your car, "house" - something related to house, etc. Then your password might look like "alpha-car-beta-house", which is easy to remember by YOU, but hard to guess.
No one recommends a 3 word passphrase. And for the situation you were asked about - a master password for a password safe - the recommendation is a 7 word phrase.
Even if you use the limited Diceware list (7776 words) you get 7776^7 which is plenty.
Gc@b%
26 upper, 26 lower, 10 numeric, 20 special chars (which are risky to use)
82^5. 3707398432. That's weaker than the 3 words phrase from a 50,000 dictionary, which is a phrase that no-one recommends and that you rejected as being too weak.
82^5 is for just one word. Combine 7 of them and you will have strong master password, much stronger than one made from 7 common words. My master password contains 16 random characters, but it still easy for me to change it when needed. I can make it twice longer without problem, but it is hard to type already.
It is random, and it is strong. It starts with a random 60-bit number and uniquely maps it to one of 2^60 distinct two-line poems. For 120 bits, memorize four lines.
Not entirely - I just think that the concept of a "master password" is still quite a bit broken. I would love if there were more biometric ways of me proving my identity to some system that maintained all these secure tokens that was also somehow revoke-able. I realize that may relate to mental memory.
For now, I guess it looks like a master password, which yes this paper elucidates methods for. But as long as you're memorizing 1 password (not 400), then how you manage to memorize it is of fairly small systemic gain.
Comments
All passwords should not be memorable.
Once you see them as tokens that 3rd parties will probably lose, then you know our efforts should be in secure token management software (keepass, lastpass, 1password, etc).
If they aren't memorable then they are something you have, not something you know. Now you are down to one factor.
To put it another way, what would you suggest for a master password for the token management software?
Maybe the problem is that we have it backwards. Maybe it shouldn't be something you remember and push to the authentication mechanism, but something that the authentication mechanism pushes to you.
Like, what if you pick the corpus of a novel that you've read as your master password. And the password manager uses that novel plus several other novels that you have selected (but didn't read/won't read?) to give you a series of multiple choice selections to determine if you know the right book. Just a few short passages. Preferably with proper nouns stripped out.
You have to select the passages from the correct book for all the multiple choices. That way rather than recall, the memory factor is recognition. Combine it with a non-memorable token which you have to present first in order to even see the recognition factor test and you might have something workable.
The entropy of multiple choice selections is easily calculable and very low.
number of options * number of questions
This is essentially the same "password reset questions" loophole that allowed the apple cloud storage hack on a bunch of celebrities.
I didn't say to use it by itself. I said that your OTP would be required first to even access it. And of course you could provide backoff. And then you'd also have to be answering a series of multiple choice questions all correctly.
I dunno, just a thought, but do you get what I'm saying about recognition vs recall? Why don't we have the computer test us about things we're good at if part of the test has to be something only our individual brain is capable of?
Random password. Just memorize it.
You've just redefined memorable to make the problem disappear. That's not terrible useful. The idea is not to come up with a perfect solution that virtually no one will use.
The whole point of this paper is that it makes a 60-bit random password which is easy to remember.
Passwords, which are easy to remember, are not random and not strong. If I will know that your passwords are 3 dictionary words, I will try to bruteforce them using words, not characters. 50000 common words in ^3 is too small.
Jut generate random password and memorize it, like you memorize other random numbers and strings, like lock combinations, room numbers, car numbers, etc. Learn how to memorize arbitrary long strings of characters and you will have no problems with them for rest of your life.
To make life easier, memorize short password first, e.g. Gc@b%, let call it "alpha", then, when password expired, memorize two new short passwords, "beta" and "gamma", and include your old password "alpha" between them (or rotate it, or flip, or use part of it, etc.), so your password will 2 times longer and stronger. Repeat procedure next time. In short time, you will have list of "words" - short pieces of random strings, which are hard to guess by strangers, but remembered well by you. You can use that dictionary to construct new passwords while keeping adding new random or non-random "words" to dictionary, e.g. "car" - something related to your car, "house" - something related to house, etc. Then your password might look like "alpha-car-beta-house", which is easy to remember by YOU, but hard to guess.
No one recommends a 3 word passphrase. And for the situation you were asked about - a master password for a password safe - the recommendation is a 7 word phrase.
Even if you use the limited Diceware list (7776 words) you get 7776^7 which is plenty.
26 upper, 26 lower, 10 numeric, 20 special chars (which are risky to use)
82^5. 3707398432. That's weaker than the 3 words phrase from a 50,000 dictionary, which is a phrase that no-one recommends and that you rejected as being too weak.
82^5 is for just one word. Combine 7 of them and you will have strong master password, much stronger than one made from 7 common words. My master password contains 16 random characters, but it still easy for me to change it when needed. I can make it twice longer without problem, but it is hard to type already.
It is random, and it is strong. It starts with a random 60-bit number and uniquely maps it to one of 2^60 distinct two-line poems. For 120 bits, memorize four lines.
Right, and I think it's a good idea. codemac and lisivka apparently disagree.
Not entirely - I just think that the concept of a "master password" is still quite a bit broken. I would love if there were more biometric ways of me proving my identity to some system that maintained all these secure tokens that was also somehow revoke-able. I realize that may relate to mental memory.
For now, I guess it looks like a master password, which yes this paper elucidates methods for. But as long as you're memorizing 1 password (not 400), then how you manage to memorize it is of fairly small systemic gain.