PwdHash Sidebar v2.4.1resigned1
PwdHash (by Stanford) generates passwords resistant to theft and phishing by hashing a combination of the sites address and your password. It is available as browser extensions (Firefox, Chrome, Opera <12), apps (Android, iOS, Windows), scripts (Ruby, Python) or a simple web page which uses Javascript.
This version of PwdHash is both a web extension for common browsers as well a simple web page. You can install it as an add-on, use the web page as a bookmark or just save it locally.
Make sure the button is added to your toolbar, click it or press F8 to open the toolbar menu. The address is prefilled (but can be modified). After pressing return on the password field, the hash is copied to your clipboard. Alternatively you can press Ctrl+F8 to open the sidebar.