Comment by fluidcruft

I have this InputStick USB [1] dohicky that I keep with my keys shows up as a generic USB keyboard when plugged in but is also an encrypted Bluetooth dongle (part of pairing allows you to configure a shared encryption key so that only devices that know the key can use the stick, and only sticks with the key are recognized by the client apps). There's a plugin to Keepass2Android that I use to type passwords from my phone. I use that to unlock my password manager (using a giant untypable passphrase). So entering mosterous passphrases is very easy... bot only if you can unlock my phone and use biometrics to open Keepass2Android.

It really is dumb that phones can just generically play USB HID (without running custom kernels)

[1] http://inputstick.com/

[2] http://inputstick.com/kp2a-plugin/