Using a smart grid, which increases efficiency and makes it easier to monitor critical equipment in a power grid. Online real-time applications equipped with a wireless sensor network (WSN) sense and collect data in order to provide information on power generation, transmission, distribution, and customer. Applications, the administrator, and (mobile) consumers can access the WSN directly. The communications between them must be protected from adversaries to avoid false data injection, which could cause damage either to the applications, the equipment, or the sensor nodes. Another threat comes from the characteristics of the sensor nodes, which makes them vulnerable to denial of services (DoS) attacks, i.e., flooding with false messages. In this paper, a multiuser dynamic cipher puzzle (M-DCP) equipped with TinySet is proposed. This new method provides guaranteed confidentiality in the multiuser WSN authentication and lightweight DoS resistance. The M-DCP using RC5 encryption combined with the elliptic curve digital signature algorithm (ECDSA) and partial recovery can increase brute force complexity to about 1.861 x 10(137) iterations. Furthermore, the regularization of TinySet is done to simplify the administrator's task in defining the initialization parameters. The experiment showed that the regularized TinySet required less storage space with a 64-bit index than with a 32-bit index or with Counting Bloom Filter. In addition, the average query and verification time of the proposed scheme increased only by under a second or 36% compared to Counting Bloom Filter-based authentication. This is still appropriate for implementation in the WSNs.
