Maybe a 1 minute delay between attempts 3 and 4. And double the time for each failure? And permanently lock after 6 attempts? Or make this configurable? I have gotten sloppy with passphrase entry more than three times in a row, so getting permanently locked out seems like a high penalty.

Interesting product though. I like the Fifth Element reference.

Moolipass project creator here! It's surprising and wonderful to see our project mentioned here. Adding a time delay between PIN attempts definitely is a good idea. I'm afraid the number of maximum attempts is fixed by the hardware we're using.