In “Secure Wireless Technology for Distribution Automation Applications” (Powergrid International, July 2012), Curt Goldman correctly states secure communication networks are critical to efficient, effective power delivery. Unfortunately, his solution for securing wireless data communications using frequency-hopping spread spectrum (FHSS) data radios does little to provide network security.
FHSS works only at Layer 1 of the OSI stack. It attempts to secure only the physical pipe for data transmission—analogous to attempting to secure the Internet by guarding only copper wires and fiber-optic cables. The threat of denial of service (DoS) and intrusion—the risks Goldman proposes to mitigate using FHSS—is well-documented for the Internet; however, these attacks are rarely conducted by breaking into the pipe. The main danger lies in unauthorized access to the ends of the pipe. FHSS does not lessen this danger. Security for wired and wireless networks requires sophisticated authorization, access control, firewalling, encryption and logging, which can defeat an attacker with physical media access. They must be implemented at multiple layers of the OSI stack to provide defense-in-depth so if an attacker defeats a security mechanism at one layer, he faces a similar mechanism at another. The security mechanism must be standards-based so the network can provide communication for devices from many vendors and can benefit from the work of the large and active Internet and enterprise security community as new threats emerge.
Bert Williams, Marketing Director
ABB Wireless Communication Systems