I really think that some sort of pin number upon opening the app, or password, would be a good implementation to personal data security.
A lot of people are trustworthy enough to use a simple “swipe to unlock” feature on their phone, or even trustworthy enough to allow their friends and family to unlock their phones.
In doing so, they then are able to access the Monzo app and are able to view all of my transactions (which, usually is something that one might need to or want to hide).
I think that upon opening the app you should always be requested some sort of security question.
One thing that some apps do, is they ask you for a secret word that they then use later on to help log you in.
For example, let’s say your secure word is ‘security123’
The app would then give you three drop downs, full of the alphabet and numerical characters available from a-z and 0-9. It might ask for the 2nd, 5th and 8th character in your secret word. You would then select e, r and y. This would then let you do access anything in the app as normal, until you close or minimize it. Then, upon reopening or maximizing the app… It would again ask you for characters within your secure word… But perhaps different ones. Maybe this time it and for the 4th, 8th and 9th character.
I think this would be good for data protection, security and just general piece of mind in case anyone goes snooping around someone else’s phone…