Password calculator
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Simple password calculator

This is a browser-based password password calculator. It takes a site name, a username, and a passphrase, then generates a long password. It has been designed to work offline on mobile devices that support HTML5 offline storage. The app doesn't store passwords or send them over the network; everything is calculated in the browser.


  • The generated passwords are hard for computers to guess, so they're safer than trying to remember a separate password for every site you use.
  • Because the passwords are calculated based on information you know, you can recalculate them whenever you like. So you don't have to save them anywhere or write them down.
  • Because each site's password is different, if that site gets hacked or your password stolen, then you don't need to worry that your other accounts will be hacked.


The idea of calculating passwords is a great idea, but it's not my idea.

The password is actually an encrypted hash. Specifically a SHA1 HMAC. The javascript implementation used is from which is new BSD licensed.

Password hashes are generated with the Password Hasher JS from -- it's MPL/GPLv2/LGPL. This means you can install that extension and get the same passwords out of it, and some other nice features too (like remembering the settings for each site).

Anything that isn't mentioned above can be assumed to be mine and new BSD licensed.