If you have a cryptographic primitive and a robust system to protect it (secure hardware, biometric auth), if you can confirm digital identity in real life you can be reasonably assured Adam is reading. Chain of integrity.
Just like blockchain, meat space applications of digital chains of trust require too much benevolence. At the end of all the state of the art crypto is Grandma pushing a button.
At its best it verifies that "Adam" is using a device that was verified by a trusted 3rd party as being added to the network by Adam himself. So, it is more about trusting devices than individual interactions.