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Generate keys Hash-function of passphrase (+ random IV (optional for K global change))

Generate keys Hash-function of passphrase (+ random IV (optional for K global change)) → global spreading code K global (& encryption key K e (optional to encrypt Identifiers)). Discovery-Beacons (D-Beacon) All nodes periodically send Discovery-Beacons

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Generate keys Hash-function of passphrase (+ random IV (optional for K global change))

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  1. Generate keys Hash-function of passphrase (+ random IV (optional for Kglobal change)) → global spreading code Kglobal (& encryption key Ke (optional to encrypt Identifiers)). Discovery-Beacons (D-Beacon) All nodes periodically send Discovery-Beacons - D-Beacons only sent for device discovery - D-Beacons are spreaded with Kglobal Device Discovery Discovery-Beacons are received periodically, indicate what/who is in range Join-Procedure No real state, only indicates what will happen next. If the Sync. Process is carried out using Kglobal for spreading, then the Sync. Process is a Join-Procedure. Sync. Code Hopping Protocol → Creates a new shared secret Si+1, from which the new key- pair [KAB,i+1, KBA,i+1] = hash64(Si+1) can be generated. This process has to be executed between each node in range. Data Communication Main state where the node communi- cates with the newly established keys [KAB,i+1, KBA,i+1]. In periodic time intervals all the nodes additionally transmit the Discovery-Beacon. Session Termination If no connectivity with node X during a specific time-interval (Termination-Timer), the keys used to communicate with that node will be deleted. Otherwise (no timeout), that node can rejoin the network by initializing a new sync-process or just continue communicating. After termination, the nodes can also rejoin the network by going through the Join-Procedure. Parameterized Privacy: - Constraint: Either number of sent packets/bytes and/or time-interval in which current keys were used. - Spreading-Factor: Increase the spreading-factor of the used keys to increase the privacy. - D-Beacon-Interval: Increase (or turn off) the D-Beacon-Interval to increase the privacy. Overview

  2. Synchronized Code Hopping Protocol: State = 1 State = 2 State = 3 State = 4 Delete old keys Timers: - TimerA1: A timeout of TimerA1 indicates the loss of the INI-ACK or the INI-SYNC packet and leads to the retransmission of the INI-SYNC packet. - TimerB1: A timeout of TimerB1 indicates the loss of the ACK-SYNC packet and leads to the retransmission of the INI-ACK packet. - TimerA2: A timeout of TimerA2 indicates that everything went fine and that the ACK-SYNC packet was received by the intended node. Otherwise the INI-ACK packet would be received during the life-span of TimerA2 (due to the loss of the ACK-SYNC packet and consequentially the timeout of TimerB1 would initiate its retransmission). - TimerB2: Thought of to postpone the deletion of the old keys and the restart of the communication- Mode with the new established keys. Maybe no communication possible during the life-span of TimerB2 (& TimerA2) to avoid the confusion between new and old keys while: TimerB1≥TimerA1 & TimerA2≥TimerB1

  3. Frame formats Format of the INI-SYNC frame Octets: 1 1 2/8 2/8 Frame Control Sequence Number Destination Address Source Address Diffie-Hellman g Diffie-Hellman p Diffie-Hellman A Format of the INI-ACK frame Octets: 1 1 2/8 2/8 Frame Control Sequence Number Destination Address Source Address Diffie-Hellman B Format of the ACK-SYNC frame Octets: 1 1 2/8 2/8 Frame Control Sequence Number Destination Address Source Address Format of the Discovery-Beacon (D-Beacon) frame Octets: 1 1 2/8 2/8 1 Frame Control Sequence Number Source Address PAN Identifier Beacon Interval Capability Information Format of the Frame Control field Format of the Capability Information field Bits: 3 1 2 2 Bits: 7 1 Frame Type Security Enabled Destination Addressing Mode Source Addressing Mode Reserved Association Permit

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