Proxy re-encryption

About: Proxy re-encryption is a research topic. Over the lifetime, 708 publications have been published within this topic receiving 33624 citations.

Improved functional proxy re-encryption schemes for secure cloud data sharing

Abstract: Recently Liang et al. propose an interesting privacy-preserving ciphertext multi-sharing control for big data storage mechanism, which is based on the cryptographic primitive of anonymous multi-hop identity based conditional proxy re-encryption scheme AMH-IBCPRE. They propose a concrete AMH-IBCPRE scheme and conclude their scheme can achieve IND-sCon-sID-CCA secure (indistinguishable secure under selectively conditional selectively identity chosen ciphertext attack). However, our research show their scheme can not be IND-sConsID- CCA secure for single-hop and multi-hop data sharing. Also in 2014, Liang et al. propose an interesting deterministic finite automata-based functional proxy reencryption scheme DFA-based FPRE for secure public cloud data sharing, they also conclude their scheme can achieve IND-CCA secure (indistinguishable secure under chosen ciphertext attack), we also show their scheme can not be IND-CCA secure either. For these two proposals, the main reason of insecurity is that part of the re-encryption key has the same structure as the valid ciphertext, thus the adversary can query on the decryption oracle with this part of the re-encryption key to get secret keys, which will break the CCA-security of their scheme.We give an improved AMH-IBCPRE scheme and an improved DFA-based FPRE scheme for cloud data sharing and show the new schemes can resist our attack and be CCA-secure.We also demonstrate our improved AMH-IBCPRE scheme’s efficiency compared with other related identity based proxy re-encryption schemes, the results show our scheme is almost the most efficient one.

A Threshold Proxy Re-Encryption Scheme for Secure IoT Data Sharing Based on Blockchain

Abstract: The IoT devices deployed in various application scenarios will generate massive data with immeasurable value every day. These data often contain the user’s personal privacy information, so there is an imperative need to guarantee the reliability and security of IoT data sharing. We proposed a new encrypted data storing and sharing architecture by combining proxy re-encryption with blockchain technology. The consensus mechanism based on threshold proxy re-encryption eliminates dependence on the third-party central service providers. Multiple consensus nodes in the blockchain network act as proxy service nodes to re-encrypt data and combine converted ciphertext, and personal information will not be disclosed in the whole procedure. That eliminates the restrictions of using decentralized network to store and distribute private encrypted data safely. We implemented a lot of simulated experiments to evaluate the performance of the proposed framework. The results show that the proposed architecture can meet the extensive data access demands and increase a tolerable time latency. Our scheme is one of the essays to utilize the threshold proxy re-encryption and blockchain consensus algorithm to support IoT data sharing.

Conditional Proxy Re-Encryption - A More Efficient Construction

Abstract: In a proxy re-encryption (PRE) scheme, Alice gives a special information to a proxy that allows it to transform messages encrypted under Alice’s public key into a encryption under Bob’s public key such that the message is not revealed to the proxy. In [14], Jian Weng and others introduced the notion of conditional proxy re-encryption (C-PRE) and proposed a system using bilinear pairings. Later, a break for the same was published in [17] and a new C-PRE scheme with bilinear pairings was introduced. In C-PRE, the proxy also needs to have the right condition key to transform the ciphertext (associated with a condition set by Alice) under Alice’s public key into ciphertext under Bob’s public key, so that Bob can decrypt it. In this paper, we propose an efficient C-PRE scheme which uses substantially less number of bilinear pairings when compared to the existing one [17]. We then prove its chosen-ciphertext security under modified Computational Diffie-Hellman (mCDH) and modified Computational Bilinear Diffie-Hellman (mCBDH) assumptions in the random oracle model.

Usable secure mailing lists with untrusted servers

Abstract: Mailing lists are a natural technology for supporting messaging in multi-party, cross-domain collaborative tasks. However, whenever sensitive information is exchanged on such lists, security becomes crucial. We have earlier developed a prototype secure mailing list solution called SELS (Secure Email List Services) based on proxy encryption techniques [20], which enables the transformation of cipher-text from one key to another without revealing the plain-text. Emails exchanged using SELS are ensured confidentiality, integrity, and authentication. This includes ensuring their confidentiality while in transit at the list server; a functionality that is uniquely supported by SELS through proxy re-encryption. In this work we describe our efforts in studying and enhancing the usability of the software system and our experiences in supporting a production environment that currently is used by more than 50 users in 11 organizations. As evidence of its deployability, SELS is compatible with common email clients including Outlook, Thunderbird, Mac Mail, Emacs, and Mutt. As evidence of its usability, the software is being used by several national and international incident response teams.