Encrypted control is a promising method for the secure outsourcing of controller computation to a public cloud. However, a feasible method for security proofs of control has not yet been developed in the field of encrypted control systems. Additionally, cryptography does not consider certain types of attacks on encrypted control systems; therefore, the security of such a system cannot be guaranteed using a secure cryptosystem. This study proposes a novel security definition for encrypted control under attack for control systems using cryptography. It applies the concept of provable security, which is the security of cryptosystems based on mathematical proofs, to encrypted control systems. Furthermore, this study analyzes the relation between the proposed security and the conventional security of cryptosystems. The results of the analysis demonstrated that the security of an encrypted control system can be enhanced by employing secure homomorphic encryption.

翻译：加密控制是将控制器计算安全外包到公共云层的一个很有希望的方法,然而,在加密控制系统领域尚未开发出可行的控制安全证明方法;此外,加密系统不考虑对加密控制系统进行某些类型的攻击;因此,无法使用安全的加密系统保证这种系统的安全;本研究报告提出了对使用加密控制系统进行攻击的加密控制的新的安全定义;它将可变安全概念,即基于数学证据的加密系统的安全,适用于加密控制系统;此外,这项研究分析了拟议的安全与加密系统常规安全之间的关系;分析结果表明,使用安全的同质加密可以加强加密控制系统的安全。