Selectively Reusing Bad Passwords Is Not a Bad Idea, Researchers Say

An anonymous reader tipped us to news that Microsoft researchers have determined that reuse of the same password for low security services is safer than generating a unique password for each service. Quoting El Reg: Redmond researchers Dinei Florencio and Cormac Herley, together with Paul C. van Oorschot of Carleton University, Canada ... argue that password reuse on low risk websites is necessary in order for users to be able to remember unique and high entropy codes chosen for important sites. Users should therefore slap the same simple passwords across free websites that don't hold important information and save the tough and unique ones for banking websites and other repositories of high-value information. "The rapid decline of [password complexity as recall difficulty] increases suggests that, far from being unallowable, password re-use is a necessary and sensible tool in managing a portfolio," the trio wrote. "Re-use appears unavoidable if [complexity] must remain above some minimum and effort below some maximum." Not only do they recommend reusing passwords, but reusing bad passwords for low risks sites to minimize recall difficulty.

Comments

Dumb dumb dumb advice...

[dskoll]

That is just so stupid. Use a password-keeper and use strong passwords everywhere. Then you only need (1) physical access to your password keeper and (2) to remember one strong passphrase.

Re:Dumb dumb dumb advice...

[jbmartin6]

This isn't stupid at all, it is something missing from a lot of security advice: a hint of reality. The amount of effort any person will put towards security, or any other goal, is finite. Therefore it is useful to put at least some thought into how that limited effort can be used for the maximum benefit. For the most part, I don't care what my gawker password is or all the other silly little logons. I use the same simple password for all of them because there is zero risk to me if they are compromised, other than someone else can now post with the screen name I picked (and don't care about) To suggest that I should lug around a password safe and log into it every time I need to use one of these zero risk logons is to suggest that I squander my limited security effort. It is far better to conserve that effort for things that are actually important.

Bah

[Nimey]

Using a password manager with one strong master password + randomly-generated passwords unique to each website is better.

That said, the linked paper is long and math-heavy, so I rate it likely the submitter (and the "editor") misunderstood something.

Simpler approach...

[flajann3290]

A simpler approach is to have a few high-entropy passwords and append a value at the end that is unique to each website using some self-created rule for it that is easy for you to remember. I would speak on how I do this but I won't for obvious reasons. :p

A great way to remember your passwords is to use them often. The more the better.

What kills me is that different sites have different password restrictions that infuriates me. Some force you to use "special characters", others forbid it. Some force you to use a combination of letters and numbers, and many force you to use at least one uppercase letter and one lowercase letter. Some even restrict how long your password can be!!!!

This wrecks havoc with my high-entropy passwords that now becomes useless or needing to be altered, as in capitalizing a letter that I totally forget about later...