I wrote something similar some time ago: https://addons.mozilla.org/de/firefox/addon/masterkey/ https://addons.mozilla.org/de/firefox/addon/masterkey/ https://g

I wrote something similar some time ago: https://addons.mozilla.org/de/firefox/addon/masterkey/ https://addons.mozilla.org/de/firefox/addon/masterkey/ https://github.com/ninov/masterkey-firefox https://github.com/ninov/masterkey-firefox Or as android app: https://play.google.com/store/apps/details?id=de.ninov.masterkey&hl=de https://play.google.com/store/apps/details?id=de.ninov.maste... It works by using SHA256-HMAC on the service name with your master key as key and then encoding it in Base85 or Base62 (if you don't want special characters)