복호화 위임을 제공하는 효율적인 브로드캐스트 암호시스템

다국어 초록 (Multilingual Abstract)

In a Broadcast Encryption System, a sender sends an encrypted message to a large set of receivers at once over an insecure channel and it enables only users in a target set to decrypt the message with their private keys. In 2005, Boneh et al. proposed a fully collusion-resistant public key broadcast encryption system in which the ciphertext and the privatekey sizes are constant. In general, pairing-based broadcast encryption systems are more efficient in bandwidth and storing aspects than non-pairing based broadcast encryption systems, however, they require many computational costs that resource-constrained devices are not suitable to be applied. In this paper, we propose a broadcast encryption scheme that user can decrypt a ciphertext more efficiently. The scheme is based on Boneh et al.’s scheme. More precisely, it reduces receiver’s computational costs by delegating pairing computations and other computation where O(n) size public key are used to. Furthermore, the scheme enables a user to check if the proxy server compute correctly. We show that our scheme is secure against selective IND-RCCA adversaries under the n-BDHE assumption.

목차 (Table of Contents)

• 1. Introduction
• 1.1 Overview
• 1.2 Related Work
• 1.3 Contribution
• 2. Preliminaries
• 2.1 Definition of BESDD Scheme
• 2.2 Security Model of BESDD Scheme
• 2.3 Bilinear Maps
• 2.4 l-BDHE Assmptions
• 3. BGW Scheme
• 3.1 BGW Scheme
• 3.2 Security Proof of the BGW Scheme
• 4. CPA-Secure Construction
• 4.1 Construction
• 4.2 Security Proof
• 5. RCCA-Secure Construction
• 5.1 Construction
• 5.1 Security Proof
• 6. Analysis
• 7. Conclusion