Efficient Unidirectional Proxy Re-Encryption

Abstract

Abstract. Proxy re-encryption (PRE) allows a semi-trusted proxy to convert a ciphertext originally intended for Alice into one encrypting the same plaintext for Bob. The proxy only needs a re-encryption key given by Alice, and cannot learn anything about the plaintext encrypted. This adds flexibility in various applications, such as confidential email, digital right management and distributed storage. In this paper, we study unidirectional PRE, which the re-encryption key only enables delegation in one direction but not the opposite. In PKC 2009, Shao and Cao proposed a unidirectional PRE assuming the random oracle. However, we show that it is vulnerable to chosen-ciphertext attack (CCA). We then propose an efficient unidirectional PRE scheme (without resorting to pairings). We gain high efficiency and CCA-security using the "token-controlled encryption" technique, under the computational Diffie-Hellman assumption, in the random oracle model and a relaxed but reasonable definition.

Flexible, Secure, and Reliable Data Sharing Service Based on Collaboration in Multicloud Environment

“…With a proxy server, the PRE primitive can transfer a ciphertext designated for one user to another ciphertext designated for another user without knowing the plaintext content of data. After that, many PRE schemes have been proposed for the improved security or efficiency [29][30][31]. In 2006, Ateniese et al [32] then improved the concept of PRE and employed it for remote data storage.…”

Representative System and Security Message Transmission using Re-encryption Scheme Based on Symmetric-key Cryptography

“…His scheme theoretically allows any information processing against ciphertext at impractical computational cost. Compared to his work, proxy re-encryption requires very restricted processing and many schemes have been proposed in order to achieve several different security properties [2], [4], [5], [6], [9], [10], [11], [12]. They are based on asymmetric key encryption mechanisms and provide rich flexibility in operation, but their computational cost for processing is still quite large, therefore not suitable for large scale systems such as public services.…”

A content privacy-preserving protocol for energy-efficient access to commercial online social networks

“…The security parameters of the experiment are set as follows. The group order |G| in the public-key encryption schemes, [6], [3], [8] is 512 bits and the length of symmetric key used to encrypt social content is 128 bits.…”