  For networked control systems, cyber-security issues have gained much
attention in recent years. In this paper, we consider the so-called zero
dynamics attacks, which form an important class of false data injection
attacks, with a special focus on the effects of quantization in a sampled-data
control setting. When the attack signals must be quantized, some error will be
necessarily introduced, potentially increasing the chance of detection through
the output of the system. In this paper, we show however that the attacker may
reduce such errors by avoiding to directly quantize the attack signal. We look
at two approaches for generating quantized attacks which can keep the error in
the output smaller than a specified level by using the knowledge of the system
dynamics. The methods are based on a dynamic quantization technique and a
modified version of zero dynamics attacks. Numerical examples are provided to
verify the effectiveness of the proposed methods.
