Smart electric grids, which ingest data on consumer and supplier behavior, present new security challenges for mobile systems like electric vehicles (EVs), which may be vulnerable to both physical and electronic attacks.

Jianying Zhou and Aldar Chan at the A*STAR Institute of Infocomm Research have developed an automatic security system that is intended to protect EVs from combined cyber-physical attacks.

"Most existing authentication systems merely apply cybersecurity schemes directly to the smart grid, leaving gaps in the protection," says Zhou. "The problem is especially serious for EVs, because the charging infrastructure is publicly open. Anyone could plug in an EV, even if it is stolen."

One particular risk is called the “substitution attack” in which a criminal can “digitally imitate” an EV and plug in his or her own device while the EV owner pays for the electricity.

To combat this risk, the researchers worked on improvements to the “challenge-response” protocol for online security.

"Instead of using a single challenge -- which is a random number used to test if a user really is who he claims to be - we used one challenge sent through the wireless cyber path and another challenge through a physical path or the charging cable," says Zhou. "This ensures that the EV is connected physically to the right spot in the power grid, and that it is a real EV meeting existing EV standards."

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