I think sim cards have been able to run java for quite a while[0], and who knows what else they can do. So I guess encrypted post cards it is. [0] https://www.

I think sim cards have been able to run java for quite a while[0], and who knows what else they can do. So I guess encrypted post cards it is. [0] https://www.extremetech.com/defense/161870-the-humble-sim-card-has-finally-been-hacked-billions-of-phones-at-risk-of-data-theft-premium-rate-scams https://www.extremetech.com/defense/161870-the-humble-sim-ca...