stepstep
Joined 13 years ago
Joined 13 years ago
Hopefully this happens infrequently enough that it's a non-issue anyway.
> SuperGenPass uses a one-way hash algorithm (base-64 MD5) to generate passwords. Specifically, it concatenates the master password and the domain name of the Web site (masterpassword:domain.com), hashes the result at least ten times (and until it satisfies the generated password requirements), and cuts the result to the desired length.
Yikes! MD5 is known to be broken, and 10 rounds of hashing is no defense against brute force attacks. Hashpass uses SHA-256 (not broken) and does 2^16 rounds of hashing.
Not having a database certainly has its downsides.
Re usability: I've been using it for a couple days now, and I find it pretty tolerable. It's nice to not have to memorize a new password when I sign up for something. I did change my master key once; it took about 5 minutes to update all my passwords. If you only do that once every few months or once a year, it's not so bad.
Re key strengthening: Agreed, but only salt-less schemes will work in this stateless model. Unfortunately they are few.
> Finally. What happens when the password requires to have upper case, symbols, x number of digits, min or max number of characters... If you think about it, some websites have conflicting requirements.
Addressed this in the article: "Some websites have certain requirements on passwords, e.g., at least one number and one capital letter. A simple way to meet such requirements is to append something like A9! to the generated password (and remember you did that)."
This is one of those "only use it if you know what you're doing" things.
This is not a new technique. In addition to the Stanford paper, there are several other implementations mentioned in these comments. It's a compromise, not a mistake. It is better to memorize one strong password than a dozen weak ones.
This isn't custom crypto. It's a well-known hash function that serves as a filter, transforming the passwords you would otherwise enter directly into a website's login form. It is no less secure than typing in passwords by hand.
However, the gigazillion rounds are not for nothing. That is the defense against brute force attacks, which could otherwise crack passwords even if they are random.
"If a generated password is ever compromised, you don’t need to memorize a whole new secret key and update all of your passwords. For that service only, just add an incrementing index to your secret key. For example, if your key was bananas, just use bananas2. If you can’t remember which iteration of your secret key you used for a particular service, simply try them all in order."
In particular, you don't have to use the same secret key for all websites. It's okay to slightly modify one if that password is compromised.
> "This package will install io.js v1.0.0 and npm v2.1.18 into /usr/local/. The binary /usr/local/bin/iojs will also be symlinked as /usr/local/bin/node."