HyPRE: Hybrid Proxy Re-Encryption for Secure Multimedia Data Sharing on Mobile Devices

Xinyu Feng, Cong Li, Qingni Shen, Jisheng Dong, Wenjun Qian, Yuejian Fang, Zhonghai Wu

Abstract: Due to the rapid growth of mobile internet, massive multimedia data (e.g., movies, photos, notes, etc.) on mobile devices is synchronized and shared through the cloud. During this process, public key encryption plays an important role in ensuring the confidentiality of data. However, due to the bottleneck of computing and storage resources in mobile devices, it is difficult to execute complex cryptographic algorithms on them. In this paper, we present a novel Hybrid Proxy Reencryption (HyPRE) scheme for the sharing of multimedia data on mobile devices, which empowers a semi-trusted proxy to convert a ciphertext under an identity to a new one under an expressive policy without revealing the underlying plaintext. Our scheme allows mobile devices with limited resources to encrypt data efficiently, and then to share the encrypted data to multiple entities securely. We define the HRA security for our HyPRE scheme to improve the incompleteness of the security under chosen plaintext attacks (CPA) in traditional proxy re-encryption schemes and prove it selectively secure under HRA. Experimental analysis indicates that HyPRE achieves 2× to 3× improvement in terms of re-encryption performance compared with the state-of-the-art ones.