A pair of Stanford University computer science professors unveiled today a new password scheme designed to thwart phishing at bank and other sites where a user's identity and money are at risk. Dubbed PwdHash, the technique involves hashing the user's password with the domain name of the site in a way that ensures that the target site is the real one, and not a site designed by phishers to capture user information.

"Phishing attacks fool users into sending their passwords to an unintended website," says PwdHash inventor Dan Boneh, an associate professor of computer science and electrical engineering, "and since Internet users often use the same password at many websites, a phishing attack on one site will expose their passwords at many other sites." Boneh and co-inventor John Mitchell say they can change all that.

Their research group has developed an extension to popular web browsers that overhauls the security of passwords with only the slightest change in the daily web-surfing experience. To tell PwdHash to do the hashing users have to type "@@" or the press the F2 key before typing in their password. In user tests, people had no problem remembering to enter @@, Mitchell says.

Users will have to change their passwords using PwdHash at sites where they have accounts to take advantage of PwdHash. But users can do this at their own pace, Mitchell says. "Besides, changing passwords is something people should do anyway," he says. Caveats from the developers include the fact that PwdHash does not work for the AOL browser and cannot protect users who have downloaded software that can read their keystrokes as soon as they type them.

SpoofGuard is another browser extension developed by the team. It apparently can recognize illegitimate pages and warn users when they visit them. After installing SpoofGuard, a user would only have to watch his or her screen to avoid many phishing sites. PwdHash would then be the second line of defense.

Further information and free, prototype versions of both PwdHash and SpoofGuard are online at Stanford PwdHash and Stanford SpoofGuard.