Update to my 5 star review 6 years ago: unfortunately this add-on seems to have been abandoned by its original maintainers, therefore a bug showing up in Firefox 66.0.2 and onwards renders it unusable.

I have created an alternative version: https://addons.mozilla.org/en-US/firefox/addon/pwdhash2/

(on a sidenote: I'm also the author of the pull request for migrating this extension to WebExtension two years ago)

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original review:
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I've been using it for years now and it still serves me well! Unobtrusive and simple: just prefix with @@ or F2 and your password will be a hashed one specific for this site.
No more worries when a site leaks all of the unsalted passwords.

Doesn't work anymore!

Why has this been abandoned? This is such an important feature but all addons that go into this direction get abandoned. As if there was someone who does not want the we can use safe passwords...

Ich benutze PwdHash seit vielen Jahren, als von Computerbild erstmals darüber berichtet worden war. Es erfordert keinen extra Passwort-Tresor um Passwörter im PC zu speichern.

Very convenient