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.

With the rapid popularization of current Internet of Things (IoT) technology and 5G networks, as well as the continuous updating of new service lifestyles and businesses, the era of big data processing for the IoT has arrived. However, centralizing all data for processing in the cloud can lead to issues such as communication latency and privacy breaches. To solve these problems, edge computing, as a new network architecture close to terminal data sources and supporting low latency services, has gradually emerged. In this context, cloud edge collaborative computing has become an important network architecture. With the changing security requirements and communication methods of cloud edge collaborative network architecture, traditional authentication key agreement protocols are no longer applicable. Therefore, a new IoT authentication and key agreement protocol needs to be designed to solve this problem. This study proposes an IoT accessible solution for cloud edge collaboration. This scheme adopts a chaotic mapping algorithm to achieve efficient authentication. It ensures the anonymity and untraceability of users. Following this, we conducted strict security verification using BAN logic and Scyther tools. Through experimental comparative analysis, the research results show that the protocol performs better than other schemes while ensuring security. This indicates that the protocol can achieve efficient authentication and key negotiation in cloud edge collaborative network architecture, providing a secure and reliable solution for the accessibility of the IoT.

An identity authentication scheme specially designed for cloud storage via USB token is presented in this paper. Meanwhile, a secure cloud storage model, in which the excellent features of the proposed scheme are fully displayed, is introduced and detailed cryptanalysis are implemented to illustrate that the scheme is able to achieve all the existing criteria of the USB token-based identity authentication. In addition, comparison with other related authentication schemes has been made, and the results have shown that the proposed scheme is both applicable and efficient.

Password authentication is one of the most convenient and frequently used mechanisms to provide secure remote access control. In this paper, a pairing-based password authentication scheme which draws on the experience of two previous researches is proposed, and the detailed authentication phases which utilise the good properties of bilinear pairing are illustrated. Meanwhile, strict cryptanalysis is made to clarify the good security and functionality features of the proposed scheme in defending various attacks. Besides that, some flaws of a previous scheme are analysed and theoretical comparison of the computation cost with that scheme is made. Furthermore, experiments are conducted properly and the results are shown to explain the high efficiency of the proposed scheme.