Hash It! eases using unique passwords per web site without overloading your brain by generating site-specific passwords derived from a secret master key.
It maintains compatibility with the popular Password Hasher extension for Firefox and supports the "Private Key" extension of Password Hasher Plus for Google Chrome.
For further details, refer to the web page.
If you spot any bugs or have a feature request, please drop me an e-mail (I can't reply to comments).