Google as added a free Chrome browser extension to act as a safety net which alarms you when it detects hacker activity.

Many people use the same password for multiple online accounts. If this is a case, one account can be compromised and then another.

 An article on Fortune states that Google has released a Chrome browser extension called Password Alert that acts as a tripwire whenever you enter Google credentials into an untrusted site.

“Two percent of all emails to Gmail are phishing attempts,” says Justin Kosslyn, product manager at Google Ideas.

“Gmail can fortunately filter most of them out, but millions upon millions of emails a day are trying to trick you into giving up your password.”

The new password tool was developed from Google’s own learnings from conducting internal penetration tests.

“It works like a spellchecker,” Kosslyn says, explaining the mechanism.

Kosslyn says the tool triggers based on the length of the password being typed in and Chrome stores a partial fingerprint of the password.

If the tool detects that a Google password is being reused, the alarm will set off.

With its success rate, the team decided to take the product public.

“It has caught real-world phishing attacks on Googlers,” Kosslyn says, “That’s one of things that made us very keen on open sourcing it and making it available for users as well.”

Password alert is the latest product out of Google Ideas (a 4-year-old division of Google concerned with global initiatives).

Password Alert is only compatible with the Chrome browser and Google logins for now. However, Kossyln says he would like to see the tool applied all across the web and used with different services.