EnBW, a large German energy provider, has recently introduced Autocharge to its network. This process allows users to simply plug in their vehicle and charging runs automatically using the car’s MAC address. Although this has been well-received among EnBW customers, experts have raised concerns about security limitations compared to the modern, secure, and flexible Plug and Charge (PnC) process.
PnC uses asymmetric encryption, where a public key encrypts messages but can no longer decrypt them. This method allows for the creation of a certificate chain that can be checked up to the root, ensuring secure transmission and authentication. The vehicle manufacturer installs a root certificate and a vehicle certificate chained to it, called a “Provisioning Certificate ID”. The infrastructure provider also stores the provisioning certificate, so the vehicle can be recognized and contracts can be established with an energy seller.
In contrast, Autocharge relies only on a vehicle’s MAC address for billing, and it does not have any authentication or security mechanisms. While charging cards have not had significant problems with misuse, they are considered to be quick-and-dirty transitional solutions that will be gradually replaced by PnC and normal payment infrastructure over the next 5 to 15 years.
Despite its complexity, PnC offers advantages such as flexibility, and BMW and other major manufacturers are rolling out PnC-equipped electric vehicles. While Autocharge may be a convenient interim solution for charging electric vehicles, experts recommend implementing PnC for its secure and modern authentication and charging rights management.
