Tao Feng^1,*, Hongmei Pei¹, Rong Ma¹, Youliang Tian², Xiaoqin Feng³

CMC-Computers, Materials & Continua, Vol.66, No.1, pp. 871-890, 2021, DOI:10.32604/cmc.2020.012146

Abstract Data privacy is important to the security of our society, and enabling authorized users to query this data efficiently is facing more challenge. Recently, blockchain has gained extensive attention with its prominent characteristics as public, distributed, decentration and chronological characteristics. However, the transaction information on the blockchain is open to all nodes, the transaction information update operation is even more transparent. And the leakage of transaction information will cause huge losses to the transaction party. In response to these problems, this paper combines hierarchical attribute encryption with linear secret sharing, and proposes a blockchain data privacy protection control scheme based… More >

Lejun Zhang^1,2,*, Minghui Peng¹, Weizheng Wang³ , Yansen Su⁴, Shuna Cui^5,6, Seokhoon Kim⁷

CMC-Computers, Materials & Continua, Vol.66, No.1, pp. 499-515, 2021, DOI:10.32604/cmc.2020.012205

Abstract In the digital era, electronic medical record (EMR) has been a major way for hospitals to store patients’ medical data. The traditional centralized medical system and semi-trusted cloud storage are difficult to achieve dynamic balance between privacy protection and data sharing. The storage capacity of blockchain is limited and single blockchain schemes have poor scalability and low throughput. To address these issues, we propose a secure and efficient medical data storage and sharing scheme based on double blockchain. In our scheme, we encrypt the original EMR and store it in the cloud. The storage blockchain stores the index of the… More >

Hao Chen¹, Wunan Wan^{1, *}, Jinyue Xia^{2, *}, Shibin Zhang¹, Jinquan Zhang¹, Xizi Peng¹, Xingjie Fan¹

CMC-Computers, Materials & Continua, Vol.65, No.3, pp. 2441-2453, 2020, DOI:10.32604/cmc.2020.011824

Abstract As a new form of network, the Internet of things (IoT) is becoming more widely used in people’s lives. In this paper, related theoretical research and practical applications of the IoT are explored. The security of the IoT has become a hot research topic. Access controls are methods that control reasonable allocations of data and resources and ensure the security of the IoT. However, most access control systems do not dynamically assign users’ rights. Additionally, with some access control systems, there is a risk of overstepping other user’s authority, and there may exist a central authority that is a single… More >

Muqadar Ali, Chungen Xu^*, Abid Hussain

Journal of New Media, Vol.2, No.1, pp. 31-43, 2020, DOI:10.32604/jnm.2020.09946

Abstract Attribute-based encryption is cryptographic techniques that provide flexible data access control to encrypted data content in cloud storage. Each trusted authority needs proper management and distribution of secret keys to the user’s to only authorized user’s attributes. However existing schemes cannot be applied multiple authority that supports only a single keywords search compare to multi keywords search high computational burden or inefficient attribute’s revocation. In this paper, a ciphertext policy attribute-based encryption (CP-ABE) scheme has been proposed which focuses on multi-keyword search and attribute revocation by new policy updating feathers under multiple authorities and central authority. The data owner encrypts… More >

Li Ma, Meng Zhao^*, Dongchao Ma, Yingxun Fu

Journal of New Media, Vol.2, No.1, pp. 11-20, 2020, DOI:10.32604/jnm.2020.09715

Abstract Low-power wide area network (LPWAN) has developed rapidly in recent years and is widely used in various Internet of Things (IoT) services. In order to reduce cost and power consumption, wide coverage, LPWAN tends to use simple channel access control protocols, such as the Aloha protocol. This protocol is simple with poor extension capability. In high-density environment, Aloha protocol will lead to low channel utilization, prolonged access and high conflict probability. Therefore, in order to solve the above problems, we propose an enhanced channel access control mechanism based on the existing LoRaWAN protocol, that is, a dynamic listening backoff mechanism.… More >

Jun Li^{1, 2}, Jieren Cheng^{2, *}, Naixue Xiong³, Lougao Zhan⁴, Yuan Zhang¹

CMC-Computers, Materials & Continua, Vol.65, No.1, pp. 723-741, 2020, DOI:10.32604/cmc.2020.011272

Abstract Security and privacy issues have become a rapidly growing problem with the fast development of big data in public health. However, big data faces many ongoing serious challenges in the process of collection, storage, and use. Among them, data security and privacy problems have attracted extensive interest. In an effort to overcome this challenge, this article aims to present a distributed privacy preservation approach based on smart contracts and Intel Software Guard Extensions (SGX). First of all, we define SGX as a trusted edge computing node, design data access module, data protection module, and data integrity check module, to achieve… More >

Lei Li¹, Chungen Xu^{1, *}, Xiaoling Yu¹, Bennian Dou¹, Cong Zuo²

Journal of Cyber Security, Vol.2, No.1, pp. 9-23, 2020, DOI:10.32604/jcs.2020.06313

Abstract Searchable encryption technology makes it convenient to search encrypted data with keywords for people. A data owner shared his data with other users on the cloud server. For security, it is necessary for him to build a fine-grained and flexible access control mechanism. The main idea of this paper is to let the owner classify his data and then authorizes others according to categories. The cloud server maintains a permission matrix, which will be used to verify whether a trapdoor is valid or not. In this way we can achieve access control and narrow the search range at the same… More >

Zhengtao Liu^{1, *}, Yun Yang¹, Wen Gu¹, Jinyue Xia²

CMC-Computers, Materials & Continua, Vol.64, No.2, pp. 1233-1245, 2020, DOI:10.32604/cmc.2020.010846

Abstract Most cloud services are built with multi-tenancy which enables data and configuration segregation upon shared infrastructures. It offers tremendous advantages for enterprises and service providers. It is anticipated that this situation will evolve to foster cross-tenant collaboration supported by Authorization as a service. To realize access control in a multi-tenant cloud computing environment, this study proposes a multi-tenant cloud computing access control model based on the traditional usage access control model by building trust relations among tenants. The model consists of three submodels, which achieve trust relationships between tenants with different granularities and satisfy the requirements of different application scenarios.… More >

Zhengtao Liu^{1, *}, Yi Ying¹, Yaqin Peng¹, Jinyue Xia²

CMC-Computers, Materials & Continua, Vol.63, No.2, pp. 861-871, 2020, DOI:10.32604/cmc.2020.07142

Abstract Multi-tenant collaboration brings the challenge to access control in cloud computing environment. Based on the multi-tenant role-based access control (MTRBAC) model, a Temporal MT-RBAC (TMT-RBAC) model for collaborative cloud services is proposed. It adds the time constraint between trusted tenants, including usable role time constraint based on both calendar and interval time. Analysis shows that the new model strengthens the presentation ability of MT-RBAC model, achieves the finergrained access control, reduces the management costs and enhances the security of multitenant collaboration in cloud computing environment. More >

Qin Liu¹, Tinghuai Ma^{1, 2, *}, Fan Xing¹, Yuan Tian³, Abdullah Al-Dhelaan³, Mohammed Al-Dhelaan³

CMC-Computers, Materials & Continua, Vol.62, No.3, pp. 1143-1159, 2020, DOI:10.32604/cmc.2020.04949

Abstract Nowadays, the scale of the user’s personal social network (personal network, a network of the user and their friends, where the user we call “center user”) is becoming larger and more complex. It is difficult to find a suitable way to manage them automatically. In order to solve this problem, we propose an access control model for social network to protect the privacy of the central users, which achieves the access control accurately and automatically. Based on the hybrid friend circle detection algorithm, we consider the aspects of direct judgment, indirect trust judgment and malicious users, a set of multi-angle… More >