There has been a surge of interests in the security of cyber-physical systems(CPSs), yet it is commonly assumed that the adversary has a full knowledge of physical system models. This paper argues that such an unreali...There has been a surge of interests in the security of cyber-physical systems(CPSs), yet it is commonly assumed that the adversary has a full knowledge of physical system models. This paper argues that such an unrealistic assumption can be relaxed: the adversary might still be able to identify the system model by passively observing the control input and sensory data. In such a setup, the attack with knowledge of input-output data can be categorized as a Known-Plaintext Attack. A necessary and sufficient condition has been provided, under which the adversary can uniquely obtain the knowledge of the underlying physical system.From the defender's perspective, a secure controller design—which exhibits a low rank structure—is proposed which renders the system unidentifiable to the adversary, while trading off the control system's performance. Finally, a numerical example has been provided to demonstrate the effectiveness of the proposed secure controller design.展开更多
This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a nu...This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a number of secret keys invalid; (2) It is insensitive to the change of the secret key; (3) It is insensitive to the change of the plain-image; (4) It can be broken with only one known/chosen plaintext; (5) It has some other minor defects. The proposed cryptanalysis discourages any use of the scheme in practice.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 91748112)the National Key Research and Development Program of China (Grant No. 2018AAA0101601)。
文摘There has been a surge of interests in the security of cyber-physical systems(CPSs), yet it is commonly assumed that the adversary has a full knowledge of physical system models. This paper argues that such an unrealistic assumption can be relaxed: the adversary might still be able to identify the system model by passively observing the control input and sensory data. In such a setup, the attack with knowledge of input-output data can be categorized as a Known-Plaintext Attack. A necessary and sufficient condition has been provided, under which the adversary can uniquely obtain the knowledge of the underlying physical system.From the defender's perspective, a secure controller design—which exhibits a low rank structure—is proposed which renders the system unidentifiable to the adversary, while trading off the control system's performance. Finally, a numerical example has been provided to demonstrate the effectiveness of the proposed secure controller design.
基金the National Basic Research Program of China(No. 2006CB303104)the City University of Hong Kong under theSRG Project, China (No. 7002134)
文摘This paper studies the security of an image encryption scheme based on the Hill cipher (Ismail et al., 2006) and reports its following problems: (1) There is a simple necessary and sufficient condition that makes a number of secret keys invalid; (2) It is insensitive to the change of the secret key; (3) It is insensitive to the change of the plain-image; (4) It can be broken with only one known/chosen plaintext; (5) It has some other minor defects. The proposed cryptanalysis discourages any use of the scheme in practice.
