3.8 Cyber Security Issues Affecting Distribution
3.8.2 Cyber Security Requirements
The principle cyber security goal is for “end-to-end” security, meaning that there are no gaps or weak areas that an attacker could exploit (i.e. the strength of a chain is measured by the strength of its weakest link). Absolute security is impossible, but minimizing the weaknesses must be the main focus. Using state-of-the-art security technologies and defense-in-depth strategies are key ways to improve overall security. NISTIR 7628 provides excellent guidelines on cyber security of the power industry, while the NERC Critical Infrastructure Protection (CIP) 002-009 standards provide cyber security requirements for the bulk power system, some of which can be applied to distribution systems and DER systems.
Cyber security applies to both communications between entities and to stored information. The most complex for distribution and DER management is cyber security for communications since so many stakeholders are involved which are not under a single management.
Cyber security technologies were primarily developed by the information technology (IT) industry to protect against malicious attackers, while the power industry has developed many engineering strategies and operational techniques to secure the power system against inadvertent problems such as equipment failures and natural disasters. Only in combination can cyber security and power system security mechanisms provide the resilience needed to operate the Smart Grid.
IT cyber security is typically seen as providing confidentiality, integrity, and availability to cyber assets, while power system security is based on engineering design and operational strategies. IT and power system security strategies and technologies can be combined to provide resilience of the power system.
DER systems and their interactions with power systems have five basic security requirements, which protect them from five basic threats:
- Authentication – preventing unauthorized interactions
- Integrity – preventing the unauthorized modification or theft of information
- Confidentiality – preventing the unauthorized access to information
- Non-Repudiation/Accountability – preventing the denial of an action that took place or the claim of an action that did not take place.
- Availability/Resilience – preventing the denial of service and ensuring authorized access to information. This concept is extended in cyber-physical concepts to include the resilience of the power system: preventing outages if possible, coping with those outages, and recovering rapidly from outages
The first four security requirements are generally met by cyber security technologies, while the fifth security requirement of preventing denial of service is usually best met through engineering strategies. However, a tightly entwined combination of cyber and engineering strategies can build on each other to provide defense-in-depth and defense-in-breadth.
For DER systems, authentication and integrity are the most important security requirements, although the others follow close behind. Authentication ensures that only authorized interactions can take place, while integrity assures that DER systems operate safely and reliably, and some modifications to data located within the DER controller or sent to the DER controller may impact that safety and reliability.
Confidentiality is usually associated with market-related data and intellectual property, as well as managing security procedures and techniques. Competitors and thieves should not be able to access sensitive information.
Non-repudiation/Accountability is usually associated with financial transactions, such as responding to control commands or demand response requests. Providing time-stamped proof of receiving such a request and taking action on that request can be vital to billing and settling these transactions.