Mass penetration and market dominance of Electric Vehicles (EVs) are expected in the upcoming years. Due to their frequent charging needs, not only public and private charging stations are being built, but also V2V charging options are considered. This forms a charging network with various suppliers and EV customers which can communicate to schedule charging operations. While an app can be designed to develop matching algorithms for charging schedules, the system also needs a convenient payment method that will enable privacy-preserving transactions among the suppliers and EVs. In this paper, we adopt a Bitcoin-based payment system for the EV charging network payments. However, Bitcoin has a transaction fee which would be comparable to the price of the charging service most of the time and thus may not be attractive to users. High transaction fees can be eliminated by building a payment network in parallel to main ledger, with permission and signatures. In this paper, we design and implement such a network among charging stations and mobile EVs with flow, connectivity and fairness constraints, and demonstrate results for the feasibility of the scheme under different circumstances. More specifically, we propose a payment network optimization model for determining payment channels among charging stations. We present numerical results on the characteristics of the network model by using realistic use cases.

Recent developments in low-rate wide-area wireless technologies will enable the deployment of publish–subscribe architectures that can span larger geographical areas in the smart grid. In such a setting, typically, there is a lot of data exchange due to the increased number of multicasts/broadcasts among any device. Thus, using technologies such as long range wide area network (LoRaWAN) will leave very limited bandwidth to perform critical security management operations such as key creation and updates. If security management overhead cannot be minimized, eventually, it may risk meeting the real-time requirements for critical control messages and weakening the resilience of smart grid systems. In this article, we propose a new protocol for group key generation and renewal that not only reduces the number of messages but also minimizes the total delay of the process. The approach integrates classical Diffie–Hellman (DH) key exchange with Shamir’s secret sharing to generate a group key by initiating random pairing points and applying Lagrange interpolation. The hash-chain concept is employed to renew the group key without requiring further message exchanges, essentially achieving key renewal in a single message. The evaluation results show that our approach reduces the number of messages and the setup delay significantly compared to the alternative approaches.

While various covert botnets were proposed in the past, they still lack complete anonymization for their servers/botmasters or suffer from slow communication between the botmaster and the bots. In this paper, we first propose a new generation hybrid botnet that covertly and efficiently communicates over Bitcoin Lightning Network (LN), called LNBot. Exploiting various anonymity features of LN, we show the feasibility of a scalable two-layer botnet which completely anonymizes the identity of the botmaster. In the first layer, the botmaster anonymously sends the commands to the command and control (C&C) servers through regular LN payments. Specifically, LNBot allows botmaster's commands to be sent in the form of surreptitious multi-hop LN payments, where the commands are either encoded with the payments or attached to the payments to provide covert communications. In the second layer, C&C servers further relay those commands to the bots in their mini-botnets to launch any type of attacks to victim machines. We further improve on this design by introducing D-LNBot; a distributed version of LNBot that generates its C&C servers by infecting users on the Internet and forms the C&C connections by opening channels to the existing nodes on LN. In contrary to the LNBot, the whole botnet formation phase is distributed and the botmaster is never involved in the process. By utilizing Bitcoin's Testnet and the new message attachment feature of LN, we show that D-LNBot can be run for free and commands are propagated faster to all the C&C servers compared to LNBot. We presented proof-of-concept implementations for both LNBot and D-LNBot on the actual LN and extensively analyzed their delay and cost performance. Finally, we also provide and discuss a list of potential countermeasures to detect LNBot and D-LNBot activities and minimize their impacts.