How To Safely Store A Password

Re:How To Safely Store A Password by mfukar on Tuesday December 14, 2010 @02:30PM (#2005388)

The definition of a "weak" password is so loose it doesn't make sense to make your work factor a function of it. The most common attack on this kind of schemes is a side-channel attack, where you single out a subset of the password alphabet with a relatively small "work factor" and crack passwords which use that alphabet quickly.

BCrypt is already based on the premise that there are passwords which are easy to compute, and tries to avoid that differentiation. Why would you introduce it back in?

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Re:How To Safely Store A Password by Cushman on Tuesday December 14, 2010 @03:07PM (#2005531)

I see it as a kind of side-channel defense; take the set of passwords which it is possible to crack quickly and use the work factor to even it out so that the total time to crack a password remains relatively constant.

Of course it's a good point that the challenge then becomes determining what that set of passwords is. And not having run the numbers, I can't be sure how much room for improvement there is.

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