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Researchers Submit Patent Application, "Method and Apparatus for Resilient End-To-End Message Protection for Large-Scale Cyber-Physical System...

May 27, 2014



Researchers Submit Patent Application, "Method and Apparatus for Resilient End-To-End Message Protection for Large-Scale Cyber-Physical System Communications", for Approval

By a News Reporter-Staff News Editor at Information Technology Newsweekly -- From Washington, D.C., VerticalNews journalists report that a patent application by the inventors KIM, Young Jin (Basking Ridge, NJ); Kolesnikov, Vladimir Y. (Jersey City, NJ); Thottan, Marina (Westfield, NJ), filed on March 15, 2013, was made available online on May 15, 2014.

No assignee for this patent application has been made.

News editors obtained the following quote from the background information supplied by the inventors: "Conventional point-to-point schemes such as IPSec (IP Security), TLS (Transport Layer Security), or SRTP (Secure Real-time Transport Protocol) are widely employed for secure protection of Internet traffic. However, the point-to-point schemes are inappropriate for a large-scale CPS where centralized computation servers continuously collect fixed-size data from a massive number of embedded devices attached to the CPS infrastructure, perform real-time data analysis, and, if necessary, send control commands to embedded devices.

"First, due to their stateful property, centralized computation servers have to maintain security state per their associated embedded devices. i.e., each server needs O(NL)--memory space where N is the number of devices associated with the server and L is the size of security state. This raises server-side scalability issues for association management, performance, and restoration from failures. Next, the servers have a dependency on certificates or public-key operations for node authentication and key distribution. However, public-key based operations incur almost a hundred times more computing resources than symmetric-key operations and the size of the certificate chains is typically greater than 2K bytes. Therefore, it is difficult to implement these protocols on end devices with constrained computing power or bandwidth.

"By contrast, conventional group security schemes which address the limitations of the point-to-point schemes have the following limitations. First, legitimate publishers in a group can listen to messages from other publishers in the group (privacy violation). i.e., conventional group security schemes cannot be used for privacy-conserving infrastructures such as smart metering. Second, compromised subscribers in a group can send messages to other subscribers since they can disguise as legitimate publishers (message authentication problem). This is a well-known open problem in group communications. Third, accidental or incidental exposure of a group encryption key to attackers may result in whole system failures (key exposure resilience problem). Lastly, group encryption keys must be updated to ensure forward-backward secrecy whenever a member joins or leaves the group (key refreshment problem). For a group with N members, refreshing a key needs O(N) message exchanges in a brute-force fashion and O(log N) in tree-based approaches such as LKH (Logical Key Hierarchy). However both O(N) message exchanges and key tree managements are costly for a CPS communication network that consists of a large number of embedded devices and is likely to be built over multiple access technologies including PLCs (Power Line Communications) and IEEE 802.15.4. Accordingly, there is a need for an improved group security communications scheme."

As a supplement to the background information on this patent application, VerticalNews correspondents also obtained the inventors' summary information for this patent application: "An advance is made over the prior art in accordance with the principles of the present invention that is directed to a new approach for an end-to-end (E2E) message protection scheme for large-scale CPS s. Certain embodiments of the invention include a notion and use of the long-term key that is given on per node basis; this long term key is assigned during the node authentication phase and is subsequently used to derive encryption keys from a random number per-message sent. Certain embodiments include a notion and use of E2E authenticators. For a message sent, its E2E authenticator consists of the sender's identity and a MAC (e.g., HMAC) of the message. Certain embodiments also include a notion and use of message brokers (trusted intermediate parties placed in protected network locations) that multicast messages from publishers in a group to subscribers in the group. The use of trusted message brokers allows us to drastically reduce the overheads of secure group communication.

"Certain embodiments of the invention achieve privacy, message authentication, and key exposure, without compromising scalability and end-to-end security, compared with existing security solutions. Certain embodiments include the design of a novel strong E2E message protection scheme for large-scale CPSs. Our scheme eliminates the need for supporting costly solutions such as IPsec, TLS, or SRTP. In certain embodiments a security extension addresses message authentication problems that are known to be hard. One important performance benefit of the O(1)-state concept is that message flooding from a massive number of embedded devices during session reestablishment following server restarts or failures can be avoided.

"To address the security requirements for cyber-physical systems, embodiments of the present invention include a resilient end-to-end message protection framework, termed Resilient End-to End Message Protection or REMP, exploiting the notion of the long-term key that is given on per node basis. This long term key is assigned during the node authentication phase and is subsequently used to derive encryption keys from a random number per-message sent. Compared with conventional schemes, REMP improves privacy, message authentication, and key exposure, and without compromising scalability and end-to-end security. The tradeoff is a slight increase in computation time for message decryption and message authentication.

BRIEF DESCRIPTION OF THE DRAWING

"The teachings of the present invention can be readily understood by considering the following detailed description in conjunction with the accompanying drawings, in which:

"FIG. 1 shows an exemplary embodiment of a simplified model for a large-scale Cyber-Physical System (CPS);

"FIG. 2 shows an exemplary configuration of IPsec tunnels in an exemplary CPS;

"FIG. 3 shows an exemplary representation of link-by-link secure sessions in an exemplary CPS;

"FIG. 4 shows an exemplary representation for publisher-subscriber (pub-sub) group communications in an exemplary CPS;

"FIG. 5 shows an exemplary embodiment for a system model of pub-sub group communications for an exemplary CPS according to the present invention;

"FIG. 6 shows an exemplary embodiment for a message confidentiality scheme of REMP;

"FIG. 7 shows one exemplary embodiment for message authentication in a CPS leveraging message brokers; and

"FIG. 8 shows one exemplary embodiment of a high level block diagram of a sensor and server for use in accordance with the methodology of the present invention."

For additional information on this patent application, see: KIM, Young Jin; Kolesnikov, Vladimir Y.; Thottan, Marina. Method and Apparatus for Resilient End-To-End Message Protection for Large-Scale Cyber-Physical System Communications. Filed March 15, 2013 and posted May 15, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=386&p=8&f=G&l=50&d=PG01&S1=20140508.PD.&OS=PD/20140508&RS=PD/20140508

Keywords for this news article include: Patents, Information Technology, Information and Data Encoding and Encryption.

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Source: Information Technology Newsweekly