Or, simply a password for your Keepass database with the same entropy as 1Passwords secret key.

Anyways, it depends on the app you use. Some Keepass apps haven't even been audited for example, so security of those apps may be questionable.

> Or, simply a password for your Keepass database with the same entropy as 1Passwords secret key.

How would you remember a password of 128bit of entropy?

9-10 words chosen at random from a list of 10k common words in you native language will get you to 128 bits. Sure not trivial to memorise, but far from impossible.

You're not wrong of course - this would come with heavy UX issues though. E.g. it's hard to type 10 words into a password field without messing up. And _really_ hard on a mobile device.

1P would allow you to have a password like "1234" and still have the same key entropy as that 10 word password alone.

A mobile app could easily facilitate that by storing a "passphrase prefix" (or suffix, etc) using biometrics/device key and requiring users to enter the remainder if you don't trust the device to store the entire thing.

Here's a 142bits entropy password: CorrectHorseBatteryStaple

Also see: https://xkcd.com/936/

Depending on dictionary size, the entropy is way lower. Assuming a dictionary of 10k words, it’s only 53 bits.

That depends where you store that file. Is there a way to store this securely in a mobile device for use on the go?