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Entropy isn't sufficient to measure password strength

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Re: Entropy isn't sufficient to measure password strength

#71

Post by BeFlatXIII »

mojuba wrote: post #23
krupan wrote: post #18

When will we stop using passwords?! They are an elementary school kid “secret club” game taken way, way too far. They are totally broken. Nobody can come up with and remember good passwords. Nobody can store passwords securely. 100% busted. Instead of continuing to debate what makes a good password, we need to put our energy into better techniques altogether! No more shared secrets! Let’s talk about one-time codes, a…

In one of my current web-based projects I decided to experiment with magic links sent via email. They are pretty convenient (and secure enough) but turns out there's a problem with mobile email clients: they tend to open links in isolated embedded browsers and then forget the cookies. For most non-technical people this is a show stopper unfortunately. I then went with one-time 6-digit sign in codes that are emailed t…

Having to check my e-mail for each login is a major annoyance. Perhaps something like SQRL[0] may help.

[0]: https://sqrl.grc.com/pages/what_is_sqrl/

Re: Entropy isn't sufficient to measure password strength

#72

Post by gokdisjtrdcvv5 »

awelxtr wrote: post #60
shepherdjerred wrote: post #47

Earlier quoted context omitted.

It’s completely valid to distrust password managers. No software is free from bugs, or accidentally exposing your passwords. It might take a lot of work, but it’s certainly possible. There’s also the possibility of mismanaging your password database and losing all of your data.

> There’s also the possibility of mismanaging your password database and losing all of your data. The alternatives are same password everywhere or keeping a paper around with the passwords written in plain text. Both are equally disastrous (unless you work at home and don't ever get robbed)

I would say having it written is more secure. If you hide it in a good spot no robber is going to find it and even if they do you will almost certainly know you’ve been robbed so you can change the passwords. Not only that but I bet 99% of robbers wouldn’t have an effective plan to sell or use the passwords. Digital on the other hand has a significant chance to go undetected for a while and certainly know exactly what to do with them.

Re: Entropy isn't sufficient to measure password strength

#73

Post by mojuba »

kevincox wrote: post #70
mojuba wrote: post #23

Earlier quoted context omitted.

In one of my current web-based projects I decided to experiment with magic links sent via email. They are pretty convenient (and secure enough) but turns out there's a problem with mobile email clients: they tend to open links in isolated embedded browsers and then forget the cookies. For most non-technical people this is a show stopper unfortunately. I then went with one-time 6-digit sign in codes that are emailed t…

I find this way less convienent because my password manager automatically fills in my username and password. So I can log in with 1 click. With "magic links" I need to enter my email (which may be autocompleted, but it is much less reliable) and then wait for the email to show up. (Assuming I have my email available.) Also email is never going to be reliably "instant" spam techniques include bouncing an email and wai…

I know but it comes at a price of some users who don't use a password manager setting silly weak passwords.

In one of my mobile apps that manages KeyChain user/passwords correctly, I still see a lot of password reset requests. I can't even think of a reason why people would ignore autofill so often. The result is, although I haven't checked, but wouldn't be surprized if there were still a lot of "password123"'s in the DB.

So neither are passwords a good option, it seems.

Re: Entropy isn't sufficient to measure password strength

#74

Post by jjk166 »

awelxtr wrote: post #60
shepherdjerred wrote: post #47

Earlier quoted context omitted.

It’s completely valid to distrust password managers. No software is free from bugs, or accidentally exposing your passwords. It might take a lot of work, but it’s certainly possible. There’s also the possibility of mismanaging your password database and losing all of your data.

> There’s also the possibility of mismanaging your password database and losing all of your data. The alternatives are same password everywhere or keeping a paper around with the passwords written in plain text. Both are equally disastrous (unless you work at home and don't ever get robbed)

Or finding a good mix between entropy and memorability so you can keep lots of strong passwords in your head, like the featured article discusses.

Re: Entropy isn't sufficient to measure password strength

#75

Post by willis936 »

Hasn't this problem been solved for decades by diceware?

Use words as your characters with a dictionary of a few thousand words. Assume an attacker knows the dictionary. Make passwords that are too long to brute force (40+ characters). Use enough words that a dictionary attack is also infeasible (4+). Add a salt if you're feeling extra spicy.

Entropy is sufficient if you use the right language model.

Re: Entropy isn't sufficient to measure password strength

#76

Post by willis936 »

kbart wrote: post #59
BoiledCabbage wrote: post #44

Earlier quoted context omitted.

Fundamentally is there any flaw with this method? Or a reason why it isn't better than general password approach?

It's vulnerable to the dictionary-based attacks that are very common.

Diceware is designed to make passwords against dictionary attacks. Estimates of diceware entropy begin with the assumption that an attacker has the dictionary. A dictionary with 6^5 entries would take 6^5^N guesses to exhaust (assuming the entries are randomly chosen). 6^5^4 = 2^52.

Re: Entropy isn't sufficient to measure password strength

#77

Post by throwawayffffas »

Aerroon wrote: post #25
krupan wrote: post #18

When will we stop using passwords?! They are an elementary school kid “secret club” game taken way, way too far. They are totally broken. Nobody can come up with and remember good passwords. Nobody can store passwords securely. 100% busted. Instead of continuing to debate what makes a good password, we need to put our energy into better techniques altogether! No more shared secrets! Let’s talk about one-time codes, a…

Hopefully never. Or at least not in the near future. Almost every other method is going to have privacy implications because they will rely on something you have or something you are. You can't compel passwords in a similar way that you can compel people to give physical tokens or fingerprints or retina scans.

I agree and go even further that "something you have" is equivalent to a password. Even though "something you have" tends to be a public-secret key pair.

Re: Entropy isn't sufficient to measure password strength

#78

Post by throwawayffffas »

MattPalmer1086 wrote: post #69
MattPalmer1086 wrote: post #64

Earlier quoted context omitted.

You can calculate Shannon entropy of an individual password, as the number of bits per char. A password of "aaaaaaa" will have a much lower entropy than "axipeY7". What am I missing?

Replying to self... I guess it's not a useful measure of password strength, even if possible. Any password that doesn't repeat any letters will have identical entropy by this measure. So 123456789 will be the same Shannon entropy as Ar4e$hUa^

Entropy is really a measure of password length.

Re: Entropy isn't sufficient to measure password strength

#79

Post by throwawayffffas »

BoiledCabbage wrote: post #44
Bolkan wrote: post #5

https://xkcd.com/936/

Fundamentally is there any flaw with this method? Or a reason why it isn't better than general password approach?

You can only remember a limited number of passwords regardless of whether it's a sequence of words or a sequence of random characters. The main flaw in all these schemes is that you have to remember them. The only viable option is to use a password manager.

Re: Entropy isn't sufficient to measure password strength

#80

Post by jsmith99 »

BeFlatXIII wrote: post #71
mojuba wrote: post #23

Earlier quoted context omitted.

In one of my current web-based projects I decided to experiment with magic links sent via email. They are pretty convenient (and secure enough) but turns out there's a problem with mobile email clients: they tend to open links in isolated embedded browsers and then forget the cookies. For most non-technical people this is a show stopper unfortunately. I then went with one-time 6-digit sign in codes that are emailed t…

Having to check my e-mail for each login is a major annoyance. Perhaps something like SQRL[0] may help. [0]: https://sqrl.grc.com/pages/what_is_sqrl/

How is this better than oauth (assuming you use a provider who doesn't have or doesnt share your real name).
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