A variable length fast Message Authentication Code for secure communication in smart grids

We propose a variable length Message Authentication Code (MAC) scheme for secure communication between Automated Metering Interface (AMI) devices and collector nodes in the smart grid. We prove the security of this scheme and analyze its performance with respect to three attributes namely: (i) communication overhead, (ii) verification delay and (iii) memory usage. The proposed scheme reduces the time for verification by at least two orders compared to existing hash based authentication protocols. The scheme thus provides an efficient solution to support high frequency exchange of large volume messages.