Efficient certificate revocation management schemes for IoT-based advanced metering infrastructures in smart cities

Advanced Metering Infrastructure (AMI), which refers to the communication network for the collection of power data from smart meters in a Smart Grid, is expected to be used in the service of many Smart City applications such as gas and water data collection or electric vehicle charging. As the communication within the AMI needs to be secure to protect user's power data, key management becomes a challenge due to its overhead and limited resources on smart meters. While using public-keys eliminate some of the overhead of key management as opposed to symmetric-key management, there are still challenges regarding the management of certificates that store and certify the public-keys. In particular, distribution and storage of certificate revocation list (CRL) is major a challenge due to cost of distribution and storage in AMI networks which is envisioned to utilize wireless mesh networks. Motivated by the need of keeping the CRL distribution and storage cost effective and scalable, in this paper, we present a distributed CRL management scheme by utilizing distributed hash trees (DHTs) that have been heavily employed in peer-to-peer (P2P) networks. The basic idea is to share the burden of storage of CRLs among all the smart meters by exploiting the convenient wireless communication capability of the smart meters among each other. Using DHTs not only reduces the space requirements for CRLs but also makes the CRL updates more convenient. We implemented DHT-based CRL structure both on ns-3 and testbed using IEEE 802.11s mesh standard as a model for AMI and demonstrated its superior performance with respect to traditional methods of CRL management through extensive simulations. (C) 2018 Published by Elsevier B.V.