With the newest and coolest feature of passphrase generator finally merged in, I find this request even more opportune - as you could tell, I have a LONG passphrase as master key for any of my databases, so my opinion may be a little biased 😄

A rationale for this feature request is best explained by the author of keepass2android. I use this app regularly on a daily base and could not even think of practically handling the unlock procedure without this service. Here it goes, step by step (courtesy of https://keepass2android.codeplex.com/)

You should protect your password database with a strong (i.e. random and LONG) password including upper and lower case as well as numbers and special characters. Typing such a password on a mobile phone every time you unlock your database is time-consuming and error-prone.

• Use a strong password for your database
• Load your database and type the strong password once. Enable QuickUnlock
• The application is locked after the time specified in the settings
• If you want to re-open your database, you can type just a few characters (by default, the last 3 characters of your password) to unlock quickly and easily!
• If the wrong QuickUnlock key is entered, the database is locked and the full password is required to re-open

Is this safe? First: it allows you to use a really strong password, this increases safety in case someone gets your database file. Second: If you loose your phone someone seize your laptop and tries to open your password database, the attacker has exactly one chance to make use of QuickUnlock. When using 3 characters and assuming 70 characters in the set of possible characters, the attacker has a 0.0003% chance of opening the file. If this sounds still too much for you, choose 4 or more characters in the settings.

I am not an expert on how this should be done correctly from a crypto perspective, but I am available and open to collaborations so to have this feature implemented ✅