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

Re:This makes sense.

[Anonymous Coward]

The point of password reuse is to use an algorithm that you can remember but not someone can guess.

This is not my password but it's an example of how I create one:
If I visit a site and it's name is GoogleSucks.com, I will use my "easy" word + the first syllable of the site + a padding word that I use on all sites, Depending on how asinine the password requirements are, the beginning or end of the password will be padded with numbers and symbols, but always the same ones.
So Googlesucks.com might be turkeyGootrucking8
and another site like a bank site that I want higher entrophy on will use a different algorithm, so BOA might end up a hard non-englisht word + the passing word, then the company's initials + needed password entrophy, so BOA would end up with namastetruckingBOA8

So when I use sites that want to remember my shipping address or credit card (I never save my credit card number, I don't care how "safe" your site is) I use the harder credentials. I just want to post a comment on the many HuffPo type of sites, easy password all the time. So while each password for each site is unique, effectively the easy password is reused but padded with something unique to the site so that even if the password was stolen it's unusable for any other site.