{
  "id": "2109.10718",
  "version": "v1",
  "published": "2021-09-22T13:22:32.000Z",
  "updated": "2021-09-22T13:22:32.000Z",
  "title": "Input-Output History Feedback Controller for Encrypted Control with Leveled Fully Homomorphic Encryption",
  "authors": [
    "Kaoru Teranishi",
    "Tomonori Sadamoto",
    "Kiminao Kogiso"
  ],
  "comment": "13 pages, 6 figures",
  "categories": [
    "eess.SY",
    "cs.CR",
    "cs.SY"
  ],
  "abstract": "Protecting the parameters, states, and input/output signals of a dynamic controller is essential for securely outsourcing its computation to an untrusted third party. Although a fully homomorphic encryption scheme allows the evaluation of controller operations with encrypted data, an encrypted dynamic controller with the encryption scheme destabilizes a closed-loop system or degrades the control performance due to overflow. This paper presents a novel controller representation based on input-output history data to implement an encrypted dynamic controller that operates without destabilization and performance degradation. An algorithm for efficient encrypted control computation is also proposed using single instruction/multiple data operations based on a batching technique. Furthermore, this study analyzes the stability and performance degradation of a closed-loop system caused by the effects of controller encryption. A numerical simulation demonstrates the feasibility of the proposed encrypted control scheme, which inherits the control performance of the original controller at a sufficient level.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-09-22T13:22:32.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "input-output history feedback controller",
      "leveled fully homomorphic encryption",
      "encrypted control",
      "encrypted dynamic controller",
      "performance degradation"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 13,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}