Estimating Coordinator Memory Exhaustion during Large Scale Mesh Node Provisioning
Provisioner memory exhaustion during large mesh commissioning is prevented by sizing SRAM to hold concurrent DTLS context peaks plus routing table expansion
Replay Protection List
Meaning
Security mechanisms in mesh networks prevent attackers from re-sending captured packets by maintaining a record of previously seen sequence numbers. A replay protection list stores the identifiers of the most recent messages from each node in the network. If a message arrives with an old sequence number, the receiver discards it as a potential attack.
Sequence Tracking
Incrementing a counter for every sent packet ensures that each message has a unique identifier that can be verified by the receiver. The replay protection list compares the incoming counter with the last known value for that specific sender. This comparison is a fast and effective way to filter out duplicate traffic and protect the integrity of the communication.
Attack Prevention
Blocking the execution of repeated commands protects the system from unauthorized actions, such as opening a door lock twice. A replay protection list is essential for preventing an observer from recording a valid command and playing it back later to gain access. This defense is a standard requirement for any secure wireless protocol used in access control or financial transactions.
List Management
Storing the sequence numbers for a large number of nodes requires a significant amount of memory and efficient lookup algorithms. The replay protection list must be updated every time a valid message is received to stay current with the network state. In devices with limited memory, the list might only store the counters for the most frequent communicators or use a bloom filter to save space.
If the list becomes full, the device must decide which entries to remove, which could potentially leave it vulnerable to replay attacks from those specific nodes. Regular synchronization of the sequence numbers during the network join process ensures that the list remains accurate even after a device reset or power cycle.