Please make it so visible text is unreadable in other character's hands. This could be added back as a perk for something like image enhancement or telephoto lenses for cybereyes.
Reading encryption keys, phone numbers, names of people on paydata documents, business cards, etc. from someone else's hands seems to be very implausible given the overall population density and busy nature of the dome.
Alternatively, this could be a (very difficult) stat check against the relevant stats, and use something like the langue obfuscation code ported over to obfuscate text on a document in someone else's hands.