A hacker, by definition, isn't dishonest. A hacker is just someone curious and technically savy.

About the 8031... I think it's a device intended (in the old days) to be used for development, instead of using one of the special 8051 with an internal EPROM and quartz window you choose a 8031 and an external EPROM.

Since it was external and discrete an EPROM is easily cracked, at most it could be programmed with bits scrambled (data and/or address) but someone with a working brain and a little imagination could figure how to descramble it.

what I have read to do some clever scrambling was to decode the eprom using a 8051 with a descrambling software, and since it an internal program it couldn't be read. Some arcade machines from the '80s used it.

if you need security you must choose a more adequate variant than the plain 8031