US 12,411,951 B2
System and method for security control in cyber-physical systems with delay-induced feedback watermarking
Christoforos Somarakis, Gilroy, CA (US); Raman Goyal, Mountain View, CA (US); Erfaun Noorani, Fairless Hills, PA (US); and Shantanu Rane, Palo Alto, CA (US)
Assigned to Xerox Corporation, Norwalk, CT (US)
Filed by Palo Alto Research Center Incorporated, Palo Alto, CA (US)
Filed on Dec. 22, 2022, as Appl. No. 18/087,477.
Prior Publication US 2024/0211593 A1, Jun. 27, 2024
Int. Cl. G06F 21/55 (2013.01); G06F 21/62 (2013.01)
CPC G06F 21/556 (2013.01) [G06F 21/6218 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A computer-implemented method for secure control of a physical system, the method comprising:
obtaining measurement of one or more sensors associated with the physical system;
estimating a state of the physical system based on the measurement of the sensors;
generating a feedback control signal based on the estimated state;
generating a watermarking signal based on a stored estimated state of the physical system at a previous time instant, wherein generating the watermarking signal comprises:
generating a random delay within a predetermined time range based on a predetermined probability mass function;
obtaining the stored estimated state based on the random delay such that a difference between the previous time instant and a current time instant equals the random delay; and
multiplying the stored estimated state by a predetermined scale factor, which further comprise tuning the predetermined scale factor to ensure that the watermarking signal is within an admissible input range of the physical system;
generating a watermarked control signal by combining the feedback control signal and the watermarking signal; and
applying the watermarked control signal to the physical system to regulate the state of the physical system, thereby facilitating secure control of the physical system.