Replacing Cryptographic Keys in AMI Mesh Networks with Small Latency

Abstract

Advanced Metering Infrastructures (AMI) facilitate efficient and reliable exchange of electricity information between the homes and utilities. Their unique characteristics (e.g., connecting millions of smart meters; accessing customers' private information), however, make them a lucrative target for adversaries. For example, an attacker might try to compromise the head-end of an AMI and send "remote disconnect commands" to the smart meters, disconnecting a large number of customers. To implement message authentication and protect message integrity and confidentiality, a number of cryptographic keys are being utilized. A "command key", for example, signs messages that are sent from the head-end to the meters. Such keys, however, introduce their own set of problems if they ever get compromised. A stolen command key would allow an adversary to continuously send malicious commands to the meters. Hence, the compromised keys must be revoked and replaced as quickly as possible. This paper proposes an efficient and reliable key distribution framework for the AMI mesh networks based on the connected dominating set approach. The keys are replaced with minimal latency through our "hexagon-tile coloring scheme", which allows the maximum number of keys to be transmitted in parallel, free of collision.