Proxy Broadcast Re-encryption Research Articles

A Secure Fine-Grained Micro-Video Subscribing System in Cloud Computing

Micro-video sharing is prevalent nowadays due to the rapid development of personal smart devices, fast growing of network bandwidth and the easy-to-use cloud computing. However, the micro-video sharing system is more vulnerable compared to the conventional video service model because of the vulnerability of the cloud and the hardware computing constraints of personal devices. Ensuring the security and privacy of the micro-videos has become critical for micro-video sharing systems. Recently, a number of encryption schemes have been proposed to protect the security of the micro-videos stored in the cloud. However, these approaches cannot support micro-video sharing functionality. Moreover, the encryption-based method cannot provide the fine-grained access control on encrypted micro-videos. In this paper, we present a notion of fine-grained identity-based broadcast proxy re-encryption to address the issue of fine-grained encrypted micro-video sharing. Further, we present a concrete scheme in the proposed notion and proved its semantic security. Performance and evaluation reveal that our scheme is practical and efficient.

A Secure Multimedia Data Sharing Scheme for Wireless Network

A large number of wireless devices like WiFi cameras and 4G robots have been deployed in the rapidly growing wireless network such as Internet of Things. All of the devices (sensors) are collecting and analyzing multimedia data all the time while they are actively working, and it is also required to share data among these the sensors. Typically, the wireless data is transmitted through the network gateway or the cloud platforms. In such a wireless environment, if there is no appropriate protection to the data, it is easy to cause potential data leakage. In reality, the owner of the sensor might only want to share the multimedia data stored in the sensor with a trusted third party (e.g., a family member or a coworker) through an internet gateway or the cloud platform. Ideally, the gateway or the cloud platform in the wireless network should transform one user’s encrypted data (wireless multimedia data) directly into another ciphertext under a set of new users (e.g., a trusted third party) without accessing the user’s plaintext data. In this work, a new secure notion called fuzzy-conditional proxy broadcast re-encryption (FC-PBRE) is presented to address the concern. In a FC-PBRE scheme, the proxy (the gateway or cloud server) uses a broadcast re-encryption key to re-encrypt the encrypted wireless multimedia data which can be decrypted by a set of delegatees if and only if the broadcast key’s conditional set W is close to the conditional set W′ of the ciphertext. With the FC-PBRE scheme, the wireless multimedia data is not disclosed and cannot be learnt by the proxy (the gateway or cloud server). In this paper, we first present the definition of security against chosen-ciphertext attacks for FC-PBRE. Second, we propose an efficient fuzzy-conditional proxy broadcast re-encryption scheme. Third, we prove that our FC-PBRE scheme is CCA-secure in the random oracle model based on the Decisional nBDHE assumption.

Privacy preserving cloud data sharing system with flexible control

With the development of cloud technology, sharing date between users securely becomes more and more important. Moreover, the cloud server should provide a flexible control on sharing date. This work presents a notion named fuzzy conditional broadcast proxy re-encryption (FC-BPRE), in which a semi-honest proxy can transform a delegator’s ciphertext to a new ciphertext for a set of delegatees when the ciphertext satisfies a certain condition set by the delegator. However, the proxy cannot learn any useful information about the underlying plaintext. The proxy can convert a ciphertext, encrypted under a condition set W, to a ciphertext encrypted under a condition set W′ using a broadcast re-encryption key, if and only if S and S′ are close to each other. We first formalize the notion of FC-PBRE scheme and then proposed a construction.

A proxy broadcast re-encryption for cloud data sharing

Proxy re-encryption (PRE) enables a semi-trusted proxy to automatically convert a delegator’s ciphertext to a delegate’s ciphertext without learning anything about the underlying plaintext. PRE schemes have broad applications, such as cloud data sharing systems, distributed file systems, email forward systems and DRM systems. In this paper, we introduced a new notion of proxy broadcast re-encryption (PBRE). In a PBRE scheme, a delegator, Alice, can delegate the decryption right to a set of users at a time, which means that Alice’s ciphertext can be broadcast re-encrypted. We propose a PBRE scheme and prove its security against a chosen-ciphertext attack (CCA) in the random oracle model under the decisional n-BDHE assumption. Furthermore, our scheme is collusion-resistant, which means the proxy cannot collude with a set of delegates to reveal the delegator’s private key.

Dynamic Encrypted Data Sharing Scheme Based on Conditional Proxy Broadcast Re-Encryption for Cloud Storage

Since Cloud Service Provider is a semi-trusted party in cloud storage, to protect data from being disclosed, users’ data are encrypted before being uploaded to a cloud server. Undoubtedly, flexible encrypted data sharing is a very important demand required by cloud storage users, whereas few schemes have being designed to satisfy this demand. In this paper, based on conditional proxy broadcast re-encryption technology, an encrypted data sharing scheme for secure cloud storage is proposed. The scheme not only achieves broadcast data sharing by taking advantage of broadcast encryption, but also achieves dynamic sharing that enables adding a user to and removing a user from sharing groups dynamically without the need to change encryption public keys. Moreover, by using proxy re-encryption technology, our scheme enables the proxy (cloud server) to directly share encrypted data to the target users without the intervention of data owner while keeping data privacy, so that greatly improves the sharing performance. Meanwhile, the correctness and the security are proved; the performance is analyzed, and the experimental results are shown to verify the feasibility and the efficiency of the proposed scheme.

Chosen-ciphertext secure bidirectional proxy broadcast re-encryption schemes

A proxy re-encryption PRE scheme supports the delegation of decryption rights via a proxy, who makes the ciphertexts decryptable by the delegatee. However, how to structure a chosen-ciphertext secure proxy re-encryption scheme without pair is still an open question. In this paper, by adjusting the Schnorr signature scheme and giving the accessional ciphertext components, a bidirectional which the proxy is able to transform ciphertexts in both directions proxy broadcast re-encryption schemes PBRE was proposed without pair, and the reduction of scheme's security is the computational Diffie-Hellman CDH assumption. The proof of security shows that the proposed scheme is chosen-ciphertext attack secure in the random oracle model.

Chosen-ciphertext secure bidirectional proxy broadcast re-encryption schemes

A proxy re-encryption PRE scheme supports the delegation of decryption rights via a proxy, who makes the ciphertexts decryptable by the delegatee. However, how to structure a chosen-ciphertext secu...

Certificateless Broadcast Proxy Re-encryption With Group-Oriented Model

Certificateless Broadcast Proxy Re-encryption With Group-Oriented Model

Conditional Identity-Based Broadcast Proxy Re-Encryption and Its Application to Cloud Email

Recently, a number of extended Proxy Re-Encryptions (PRE), e.g. Conditional (CPRE), identity-based PRE (IPRE) and broadcast PRE (BPRE), have been proposed for flexible applications. By incorporating CPRE, IPRE and BPRE, this paper proposes a versatile primitive referred to as conditional identity-based broadcast PRE (CIBPRE) and formalizes its semantic security. CIBPRE allows a sender to encrypt a message to multiple receivers by specifying these receivers’ identities, and the sender can delegate a re-encryption key to a proxy so that he can convert the initial ciphertext into a new one to a new set of intended receivers. Moreover, the re-encryption key can be associated with a condition such that only the matching ciphertexts can be re-encrypted, which allows the original sender to enforce access control over his remote ciphertexts in a fine-grained manner. We propose an efficient CIBPRE scheme with provable security. In the instantiated scheme, the initial ciphertext, the re-encrypted ciphertext and the re-encryption key are all in constant size, and the parameters to generate a re-encryption key are independent of the original receivers of any initial ciphertext. Finally, we show an application of our CIBPRE to secure cloud email system advantageous over existing secure email systems based on Pretty Good Privacy protocol or identity-based encryption.

Analysis and Improvements of Several (H)IBS/IBSC/PRBE Schemes

Constructing efficient (Hierarchical) identitybased signature/signcryption ((H)IBS/IBSC) schemes in thestandard model with full security remain as open problemsfor a long time. Ren et al. constructed efficient (H)IBS/IBSCschemes with full security without random oracle in ISDPE’07 and Chinacrypt’08, . They claimed their schemescan be proved to simultaneously achieve high efficiency,short public parameters and a tight reduction. But weshall show their schemes are not secure. Furthermore, wegive improvements to these schemes which can resist theproposed attack. Proxy re-encryption is a primitive whichallows the transformation from A’s ciphertext to be B’sciphertext by using proxies, without the proxy knowing thecorresponding plaintexts or secret keys of A or B. Proxybroadcast re-encryption aims at transforming ciphertextfrom one user to a group, which is a generalization of proxyre-encryption. Recently, Sun et al. proposed a CCA-secureunidirectional proxy broadcast re-encryption in the standardmodel, we also show their scheme has some flaws.