Dear Ian, (
Other topics?)
I do not know if this is the right place to add this point, but tell me please.
I can suggest MAdES, or Message Advance Electronic Signature or TAdES Thing/Tuple Advance Electronic Signature. These are applicable when a billing action takes place with any reading. Example, the cyclometer of my rental car, or the fuel pump reading when the same car is topped up without me being present. When I am billed in a taxicab, etc.
To bill a reading some things, like the following must be put in a message (tuple) and signed: mac_address, device; timeserial, status, position and the actual reading. This must then be signed (without hashing) as the tuple is normally smaller than say 48 bytes.
This message then contains all the information and can be shipped anywhere (over secure channels) and used for billing confirmation using public key, later without reference to the device as long as the Thing's private key is not compromised.
The readings of these Things on the internet then becomes very useful. We can read and meter in the IoT space and bill it with this protocol. The reading can be shipped or stored anywhere and any change can be detected by checking the tuple against the signature.
Maybe IoT has sorted this out already?
C-:
