Loading...

A Lightweight Lattice-Based Searchable Encryption Scheme

Karimi, Mohammad Hossein | 2022

453 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55529 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Eghlidos, Taraneh
  7. Abstract:
  8. Many lattice-based public key encryption schemes are forced to use long keys. To deal with this problem, structured lattices such as NTRU can be used. Lattice-based searchable public key encryption schemes are no exception. Furthermore, in most existing searchable public key encryption schemes, it is assumed that the user searches documents with only one keyword. However, using a conjunctive keyword search, we can search for documents containing several keywords by executing the trapdoor generation algorithm only once. On the other hand, in most of the published searchable public key encryption schemes, storing and searching encrypted keywords are responsibility of a central entity called the cloud server. If the cloud server acts as a curious and semi-honest entity, it can return incorrect or incomplete search results to the user. A cloud server can also damage the confidentiality of documents stored in the cloud by executing a keyword guessing attack. Therefore, the research work of this thesis is divided into two parts. First, we design a public-key encryption with conjunctive keyword search (PECK) scheme based on a cloud server, the security of which is based on hard lattice problems. The proposed scheme is inspired by a recent scheme based on NTRU problem, in which we extend the search capability from one keyword to several keywords. In addition, we provide two solutions to strengthen the scheme against keyword guessing attack. Implementation of the scheme on a personal computer show that the proposed PECK scheme has a shorter key length and better execution speed compared to the existing lattice-based PECK schemes. Also, the trapdoor size is independent of the number of keywords, which is more efficient compared to the only recent similar scheme. In the second part of the research, we present a decentralized searchable encryption protocol by taking advantage of the decentralization feature of blockchain technology. By using smart contracts and blockchain transactions, we adjust the interactions of the data owner and the data user so that the searchable encryption scheme is verifiable, complete and revocable
  9. Keywords:
  10. Keyword Guessing Attack ; Key Encapsulation Mechanism (KEM) ; Public Key Cryptography ; Lattice-Based Cryptography ; Consortium Blockchains ; NTRU Encryption ; Public Key Encryption with Keyword Search ; Conjunctive Keywords

 Digital Object List

 Bookmark

...see more