Re: Idea about authentication

We already committed a fix for pbkdf2, the DOS vector no longer exists (at least not in this form): https://github.com/django/django/commit/68540fe4df44492571bc610a0a043d3d02b3d320 On Thursday, October 3, 2013 9:56:14 AM UTC+2, Ram Rachum wrote: > > Hi everybody, > > I've submitted the

Re: Idea about authentication

Hi everybody, I've submitted the patch, and corrected it, and it's been sitting on the issue tracker for 2 weeks without anyone commenting. Does anyone care to discuss this? I want to have this merged in, or discuss any problems in merging it in. On Sun, Sep 15, 2013 at 11:27 PM, Ram Rachum

Re: Idea about authentication

Hi, there are a few things which worry me about this patch (aside from the note from charettes). You write "and the DoS attack vector is avoided" which is not true, hashing functions are by design CPU-intensive so you are not avoiding DoS, even if hashing now consistently takes less (for short

Re: Idea about authentication

Submitted patch: https://code.djangoproject.com/ticket/21105#comment:1 On Sunday, September 15, 2013 10:09:55 PM UTC+3, Donald Stufft wrote: > > > On Sep 15, 2013, at 2:59 PM, Florian Apolloner > > wrote: > > Hi Ram, > > On Sunday, September 15, 2013 12:34:03 PM UTC+2, Ram

Re: Idea about authentication

On Sep 15, 2013, at 2:59 PM, Florian Apolloner wrote: > Hi Ram, > > On Sunday, September 15, 2013 12:34:03 PM UTC+2, Ram Rachum wrote: > Florian, I'm not sure that you read my message carefully enough. I'm not > proposing to reduce the time that PBKDF2 takes to hash. >

Re: Idea about authentication

Hi Ram, On Sunday, September 15, 2013 12:34:03 PM UTC+2, Ram Rachum wrote: > > Florian, I'm not sure that you read my message carefully enough. I'm *not > *proposing to reduce the time that PBKDF2 takes to hash. > By replacing the password with a hash before running it through PBKDF2 you are

Re: Idea about authentication

We'd want to use SHA256 but that's an OK thing to do AFAIK. I wouldn't agree to it in a security patch because it breaks backwards compatibility in a much larger way than the patch we did does. In fact we already do this with the bcrypt hasher in Django 1.6+ to solve a password truncation

Re: Idea about authentication

Florian, I'm not sure that you read my message carefully enough. I'm *not *proposing to reduce the time that PBKDF2 takes to hash. I'm proposing to keep that time just as long, but make it independent on the password length. On Sunday, September 15, 2013 1:12:31 PM UTC+3, Florian Apolloner

Re: Idea about authentication

On Sunday, September 15, 2013 11:45:29 AM UTC+2, Ram Rachum wrote: > What if instead of calculating the PBKDF2 hash of the password, we'll > calculate the PBKDF2 hash of its SHA1 hash? Then the time of checking > passwords wouldn't depend on their length, and we wouldn't even have to > place

Re: Idea about authentication

Thanks Curtis! I thought about my idea and realized it makes a brute-force attack easier, and we'd have to make the hashing stronger to compensate... Making the computation time longer for the real users logging in... So yeah, it won't help. But then I had another idea. So PBKDF2 takes a

Re: Idea about authentication

Actually, you'd just speed up their attack, since most failed attempts would be quicker than others. If you look in the crypto utils, you'll see a "constant time compare" ... this is a common thing in crypto circles to avoid leaking "how close" the guess was by how quickly the mismatch was found.

Idea about authentication

Hi guys, I just saw the new release announcement and I had an idea. What if, in addition to sorting the hard to compute hash for every password, we will also store the sha 1 hash of the first 5 characters ofthe password's sha1 hash? Wouldn't this allow us to quickly rule out 99% of passwords,