Proxy Re-Encryption was introduced by Blaze, Bleumer and Strauss to efficiently solve the problem of delegation of decryption rights. In proxy re-encryption, a semi-honest proxy transforms a ciphertext intended for Alice to a ciphertext of the same message for Bob without learning anything about the underlying message. From its introduction, several proxy re-encryption schemes in the Public Key Infrastructure (PKI) and Identity (ID) based setting have been proposed. In practice, systems in the public key infrastructure suffer from the certificate management problem and those in identity based setting suffer from the key escrow problem. Certificateless Proxy Re-encryption schemes enjoy the advantages provided by ID-based constructions without suffering from the key escrow problem.In this work, we construct the first unidirectional, single-hop CCA-secure certificateless proxy re-encryption scheme without pairing by extending the PKI based construction of Chow et al. proposed in 2010. We prove its security in the random oracle model under the Computational Diffie-Hellman (CDH) assumption. Prior to this work, the only secure certificateless proxy re-encryption scheme is due to Guo et al. proposed in 2013 using bilinear pairing. They proved their construction is RCCA-secure under q-weak Decisional Bilinear Diffie-Hellman assumption. The construction proposed in this work is more efficient than that system and its security relies on more standard assumptions. We also show that the recently proposed construction of Yang et al. is insecure with respect to the security model considered in this work.

Certificateless Proxy Re-Encryption Without Pairing: Revisited

The ubiquitous and timely access to personal health records help physicians to take critical decisions and save lives. Cloud computing has a potential to provide ubiquitous and on‐demand i...

Secure sharing of mobile personal healthcare records using certificateless proxy re‐encryption in cloud

Information-centric networking is the developing model envisioned by an increasing body of the data communication research community, which shifts the current network paradigm from host centric to data centric, well-known to information-centric networking (ICN). Further, the ICN adopts different types of architectures to extend the growth of the Internet infrastructure, e.g., name-based routing and in-network caching. As a result, the data can be easily routed and accessed within the network. However, when the producer generates contents for authentic consumers, then it is necessary for him/her to have a technique for content confidentiality, privacy, and access control. To provide the previously mentioned services, this paper presents a certificateless proxy reencryption scheme (CPRES) based on the hyperelliptic curve for access control in the content-centric network (CCN). Using certificateless PRE, the power of the key generation center (KGC) is limited to only the generation of partial keys to secure the access to the content. With the help of these partial keys, the producer further calculates keys for encryption and reencryption process. The simulation results show that the proposed scheme provides secure access to content during end-to-end communication. Moreover, the proposed CPRES scheme outperforms in terms of low computational energy and efficient utilization of communication bandwidth.

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Certificateless Proxy Reencryption Scheme (CPRES) Based on Hyperelliptic Curve for Access Control in Content-Centric Network (CCN)

我们探讨代理重新加密(PRE ) 的密码的话题，它是特殊公共密钥的 cryptosystem。一个 PRE 计划允许一个特殊实体，作为代理知道，到变换，一条消息与 delegator 的公钥加密了(说艾莉斯)，进新密文，那在 delegatee 的公钥下面被保护(说鲍勃)，并且因此，一样的消息然后能被恢复与跳私人钥匙。在这份报纸，在基于身份的背景，我们首先调查在那么叫的调停的加密和单向性的 PRE 之间的关系。我们提供把任何安全基于身份的单向性的 PRE 计划变换成一个安全基于身份的调停的加密计划的一个一般框架，并且反过来也如此。有关为单向性的 PRE 计划的安全， Ateniese 等。以前建议了作为主人秘密安全知道的一个重要性质，它要求代理和鲍勃的联盟不能暴露爱丽斯私人钥匙。在这份报纸，我们扩大观点到基于身份的背景，并且介绍一个基于身份的单向性的 PRE 计划，它不仅对在标准模型的选择密文攻击是 provably 安全的而且同时完成主人秘密安全。

New Constructions for Identity-Based Unidirectional Proxy Re-Encryption

To broaden the adoption of cloud computing, it is necessary to provide efficient security mechanisms for authorisation update, which is a core component of cloud security. In this paper, we propose an efficient and secure authorisation update mechanism, which is achieved using a double-layer encryption: inner-layer encryption and outer-layer encryption. The inner-layer encryption is performed on an original plaintext to generate ciphertext, while the outer-layer encryption is performed on a part of the inner-layer ciphertext taking a ciphertext as output. The inner-layer encryption enforces the initial authorisation policy, while the outer-layer encryption reflects the updated authorisation policy. Based on the double-layer encryption, we deal with the operations related to authorisation update including user update and data update. In addition, we implement the proposed mechanism and conduct extensive experiments. The experimental results demonstrate the efficiency and practicality of the proposed mechanism.

Efficient authorisation update on cloud data

Recently, Sur et al. introduced a new primitive named certificateless proxy re-encryption, which enjoys the advantages of certificateless public key cryptography while providing the functionalities of proxy re-encryption. They further proposed a certificateless proxy re-encryption scheme, and claimed that their scheme is secure against chosen-cipher text attacks in the random oracle model. However, by giving a concrete attack, in this paper we indicate that their PRE scheme is not secure against chosen-cipher text attacks.

Yulin Zheng

Papers

Cryptanalysis of a Certificateless Proxy Re-encryption Scheme