BACKGROUND

The present disclosure pertains to communicating between network connected devices and particularly mechanisms that synchronize anti-replay and duplicate message sequence counters in authenticated (and possibly also encrypted) multicast network protocols consisting of multiple nodes.

SUMMARY

The disclosure reveals systems for communicating over a network and between two or more network connected devices. In particular, the disclosure reveals systems which may synchronize anti-replay and duplicate message sequence counters in authenticated (and possibly also encrypted) multicast network protocols consisting of multiple nodes. In some instances, multicast traffic may be secured using a common group session key. Further, the node message sequence numbers (NMSN) may be scoped within a valid session to detect duplicate and replayed messages. Including these anti-replay and duplicate node message sequence counters in protocols is standard and assists nodes to discard unintended messages during communications. Another design element which may be seen in standard protocols is resetting sequence numbers when session key changes are required. Standard architectures like GDOI may provide mechanisms to distribute group session key to participating group members. However, due to attributes of session key (e.g., being common and used by multiple nodes), the policies around key lifetime and re-keying are very strict to ensure proper use of the key. This may force frequent re-keying of the common key in simple scenarios like node reboots. Further, frequent re-keying may also result in a dependency on an external key distribution center component, extra processing of session key transition at nodes not rebooting, and communication disruption in the network with increase in group size or during power loss which results in multiple node reboots. Additionally, it may be undesirable to have a single fault, failure or unavailability of a key distribution center component during node boot up scenarios. Similarly, it may be undesirable to have additional processing at non-booting up nodes, which may result in standard solutions unlikely to be used for applications in real time distributed control systems. Therefore, allowing a booting up node to synchronize its session keys and node message sequence numbers with the rest of the participating network nodes before it can send and receive secure multicast messages may mitigate the issues resulting from utilization of standard solutions, as described above

Accordingly, this disclosure introduces a methodology which may synchronize anti-replay and duplicate message sequence counters in authenticated (and possibly also encrypted) multicast network protocols consisting of multiple nodes. Further, this disclosure describes methods which may remove the need to rekey during boot ups and may introduce a unique manner to synchronize node sequence numbers across the secure group. In some cases, the mechanisms may allow node boot ups when key distribution components are temporarily unavailable, may discard scenarios and network churn for simultaneous multi-session key refreshes caused due to multi-node boot ups, and may remove the possibility for a booting up node to accept an older replayed message from a removed node from the network, thereby limiting the time window during which a reply attack may target a booting-up node.

