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Show HN: NullPass, a stateless password manager written in JavaScript

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Re: Show HN: NullPass, a stateless password manager written in JavaScript

#11

Post by adammacleod »

pwg wrote: post #5
adammacleod wrote: post #4

Earlier quoted context omitted.

No, not really. I do like having the length concatenated inside as well, as this provides a unique password for different lengths (useful to quickly visually identify if a password looks 'right'). Is there any reason why HMAC would be better than my current implementation? I have had a read over the article and it seems that straight SHA512 should have similar cryptographic strength. Thanks for your input!

Read the "Design Principles" section more carefully. Simple concatenation suffers from several different attack vectors.

Thank you.

I am concerned about changing the algorithm at this point in case anyone has already used it. I don't think there are any serious concerns but will report back if I find any (after taking some more time). Of course if anyone knows this stuff very well I'd be very eager for some feedback!

Re: Show HN: NullPass, a stateless password manager written in JavaScript

#12

Post by adammacleod »

nicwolff wrote: post #10
gfxmonk wrote: post #6

Have you seen SuperGenPass? It's much the same concept, and has been around for years (including browser extensions, etc). http://supergenpass.com/ For the justifiably paranoid, a web service is not going to cut it (lack of https is just the start - relying on any web service is a _lot_ of trust to put in such an Important Thing). Even if you are as trustworthy as I'd hope, it's foolish to even allow the possibility…

SuperGenPass credits me as the originator of the idea, my page is still up at http://angel.net/~nic/passwd.html . NullPass isn't a Web service, it's a one-page Javascript app like mine and SuperGenPass. But it loads a bunch of libraries, so it can't as easily be copied for safe offline or local use.

Neat! Yours looks very nice.

I never realised there were so many implementations of this floating around. It might be a neat idea to inline/reduce the libraries I used to more easily distribute for offline. Although I have to say that I don't feel this is any less safe because it can't run locally :)

Thanks for your input :)

Re: Show HN: NullPass, a stateless password manager written in JavaScript

#14

Post by kseistrup »

The problems with these master password implementations comes when you want to change the password for one site only. Sure, I can add a token in addition to the domain. But what token did I add to which domain? If I have to remember individual tokens I might as well remember the entire password. A solution could be to generate a “salt” for each domain, but then we're no longer stateless…

Re: Show HN: NullPass, a stateless password manager written in JavaScript

#15

Post by gfxmonk »

kseistrup wrote: post #14

The problems with these master password implementations comes when you want to change the password for one site only. Sure, I can add a token in addition to the domain. But what token did I add to which domain? If I have to remember individual tokens I might as well remember the entire password. A solution could be to generate a “salt” for each domain, but then we're no longer stateless…

One solution is to use a separate storage for salts (or hints, really - it doesn't need to be a complex scheme, since we're hashing it anyway).

I do this myself with supergenpass, for when a site's password DB gets compromised (a common enough occurrence these days).

Importantly, this augmented state is a convenience - it's not irreplaceable. If I find myself _without_ my list of hints, I am not completely screwed - I'll just have a harder time logging into those few sites, and it's quite likely I'll remember the right hint after a few tries from memory if I really need to.

Re: Show HN: NullPass, a stateless password manager written in JavaScript

#16

Post by eximius »

gfxmonk wrote: post #15
kseistrup wrote: post #14

The problems with these master password implementations comes when you want to change the password for one site only. Sure, I can add a token in addition to the domain. But what token did I add to which domain? If I have to remember individual tokens I might as well remember the entire password. A solution could be to generate a “salt” for each domain, but then we're no longer stateless…

One solution is to use a separate storage for salts (or hints, really - it doesn't need to be a complex scheme, since we're hashing it anyway). I do this myself with supergenpass, for when a site's password DB gets compromised (a common enough occurrence these days). Importantly, this augmented state is a convenience - it's not irreplaceable. If I find myself _without_ my list of hints, I am not completely screwed -…

This post kind of inspired me to whip this up (probably not original, but it's minimal): https://bitbucket.org/logannc/deterministichashpass

Basically the same idea but seeds a random number generator with the master password and the service name to have an infinite supply of passwords. Technically no state is needed because Python's random module is deterministic, but I will end up saving the state with the service name and the index of the random number so that I don't have to try each and every one (not that I change passwords that often, for better or worse).

And, for convenience, since I won't be saving the master password, I'm looking into adding a credential cache like sudo has.

Re: Show HN: NullPass, a stateless password manager written in JavaScript

#17

Post by pwg »

adammacleod wrote: post #11
pwg wrote: post #5

Earlier quoted context omitted.

Read the "Design Principles" section more carefully. Simple concatenation suffers from several different attack vectors.

Thank you. I am concerned about changing the algorithm at this point in case anyone has already used it. I don't think there are any serious concerns but will report back if I find any (after taking some more time). Of course if anyone knows this stuff very well I'd be very eager for some feedback!

> Of course if anyone knows this stuff very well I'd be very eager for some feedback!

Exactly why you should be considering changing the algorithm.

http://happybearsoftware.com/you-are-dangerously-bad-at-cryp...

Re: Show HN: NullPass, a stateless password manager written in JavaScript

#18

Post by kseistrup »

gfxmonk wrote: post #15
kseistrup wrote: post #14

The problems with these master password implementations comes when you want to change the password for one site only. Sure, I can add a token in addition to the domain. But what token did I add to which domain? If I have to remember individual tokens I might as well remember the entire password. A solution could be to generate a “salt” for each domain, but then we're no longer stateless…

One solution is to use a separate storage for salts (or hints, really - it doesn't need to be a complex scheme, since we're hashing it anyway). I do this myself with supergenpass, for when a site's password DB gets compromised (a common enough occurrence these days). Importantly, this augmented state is a convenience - it's not irreplaceable. If I find myself _without_ my list of hints, I am not completely screwed -…

I use the HMAC hash of the username, the site, and a ‘key’ generated at random. However, this does mean that I'm screwed if I cannot access the keys [and cannot remember the password].
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