tags: cryptography
Decentralized key distribution
Both A and B have a master key that hey have gotten physically, A sends to B its ID concatenated with a nonce. B responds with a session key that is encrypted with the master-key. A decrypts and get the key and uses it to send data that is a function in to B as an acknowledgement.
Centralized key distribution
In this approach we have a distribution center that holds a key for ever node. Consider A wants to talk to B, A starts by sending its ID and B’s ID and a noun, the center replies with a session key concatenated with data that is only encrypted for B, A then sends this data to B, this data contains the session key and information that A wants to talk. After this B replies with a noun, A decrypts this and sends data that is a function of the noun as an acknowledgment.
Other
There is another approach that is mentioned in the slides that they can use the old session key to get new session keys.