Wallet Unit
A Wallet Unit is the unique configuration a Wallet Provider gives to one Wallet User: the Wallet Instance (the app), together with the Wallet Secure Cryptographic Application and Wallet Secure Cryptographic Device that generate and protect its keys.
The ARF distinguishes a Wallet Solution, the software and service a Wallet Provider builds and offers generally, from a Wallet Unit, the specific instance of that solution issued to one user and bound to that user's own secure hardware. In everyday use, Wallet Instance is the app installed on a device, and Wallet Unit is that installed app together with the cryptographic material behind it: the pairing is what lets a Wallet Unit Attestation later prove a request came from a genuine, unmodified copy rather than a spoofed client.