Chosen-Ciphertext Secure Fuzzy Identity-Based Key Encapsulation without ROM

(1, 2, 3, 4, 5. College of Information Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, P.R.China) * corresponding author 1. E-mail: [email protected] 2. E-mail: [email protected] 3. E-mail: [email protected] 4. E-mail: [email protected] 5. E-mail: [email protected] Abstract. We use hybrid encryption with Fuzzy Identity-Based Encryption (Fuzzy-IBE) schemes, and present the first and efficient fuzzy identity-based key encapsulation mechanism (Fuzzy-IB-KEM) schemes which are chosen-ciphertext secure (CCA) without random oracle in the selective-ID model. To achieve these goals, we consider Fuzzy-IBE schemes as consisting of separate key and data encapsulation mechanisms (KEM-DEM), and then give the definition of Fuzzy-IB-KEM. Our main idea is to enhance Sahai and Waters' "large universe" construction, chosen-plaintext secure (CPA) Fuzzy-IBE, by adding some redundant information to the ciphertext to make it CCA-secure.