  Dynamic watermarking schemes can enhance the cyber attack detection
capability of networked control systems (NCSs). This paper presents a linear
event-triggered solution to conventional dynamic watermarking (CDW) schemes.
Firstly, the limitations of CDW schemes for event-triggered state estimation
based NCSs are investigated. Secondly, a new event-triggered dynamic
watermarking (ETDW) scheme is designed by treating watermarking as symmetric
key encryption, based on the limit convergence theorem in probability. Its
security property against the generalized replay attacks (GRAs) is also
discussed in the form of bounded asymptotic attack power. Thirdly, finite
sample ETDW tests are designed with matrix concentration inequalities. Finally,
experimental results of a networked inverted pendulum system demonstrate the
validity of our proposed scheme.
