Secure and efficient data collaboration with hierarchical attribute-based encryption in cloud computing

With the increasing trend of outsourcing data to the cloud for efficient data storage, secure data collaboration service including data read and write in cloud computing is urgently required. However, it introduces many new challenges toward data security. The key issue is how to afford secure write operation on ciphertext collaboratively, and the other issues include difficulty in key management and heavy computation overhead on user since cooperative users may read and write data using any device. In this paper, we propose a secure and efficient data collaboration scheme, in which fine-grained access control of ciphertext and secure data writing operation can be afforded based on attribute-based encryption (ABE) and attribute-based signature (ABS) respectively. In order to relieve the attribute authority from heavy key management burden, our scheme employs a full delegation mechanism based on hierarchical attribute-based encryption (HABE). Further, we also propose a partial decryption and signing construction by delegating most of the computation overhead on user to cloud service provider. The security and performance analysis show that our scheme is secure and efficient.     

A secure re‐encryption scheme for data services in a cloud computing environment

Cloud computing as a promising technology and paradigm can provide various data services, such as data sharing and distribution, which allows users to derive benefits without the need for deep knowledge about them. However, the popular cloud data services also bring forth many new data security and privacy challenges. Cloud service provider untrusted, outsourced data security, hence collusion attacks from cloud service providers and data users become extremely challenging issues. To resolve these issues, we design the basic parts of secure re‐encryption scheme for data services in a cloud computing environment, and further propose an efficient and secure re‐encryption algorithm based on the EIGamal algorithm, to satisfy basic security requirements. The proposed scheme not only makes full use of the powerful processing ability of cloud computing but also can effectively ensure cloud data security. Extensive analysis shows that our proposed scheme is highly efficient and provably secure under existing security model. Copyright © 2015 John Wiley & Sons, Ltd.     

A Lightweight Approach (BL-DAC) to Secure Storage Sharing in Cloud-IoT Environments

The growing advent of the Internet of Things (IoT) users is driving the adoption of cloud computing technologies. The integration of IoT in the cloud enables storage and computational capabilities for IoT users. However, security has been one of the main concerns of cloud-integrated IoT. Existing work attempts to address the security concerns of cloud-integrated IoT through authentication, access control, and blockchain-based methods. However, existing frameworks are somewhat limited by scalability, privacy, and centralized structures. To mitigate the existing problems, we propose a blockchain-based distributed access control method for secure storage in the IoT cloud (BL-DAC). Initially, the BL-DAC performs decentralized authentication using the Quantum Neural Network Cryptography (QNNC) algorithm. IoT users and edge nodes are authenticated in the blockchain deployed by distributed Trusted Authorities (TAs) using multiple credentials. The user data is classified into sensitive and non-sensitive categories using the Enhanced Seagull Optimization (ESO) algorithm. Also, the authentication to access this data is performed by a decentralized access control method using smart contract policy. Sensitive user data is encrypted using the QNNC algorithm and stored in the private cloud. In contrast, non-sensitive data is stored in the public cloud, and IPFS is used to store data in a decentralized manner with high reliability. In addition, data security is improved by using a hierarchical blockchain which improves scalability by managing the multiple blockchains hierarchically and is lightweight using Proof of Authentication Consensus (PoAH). The BL-DAC is simulated and validated using the Network Simulator-3.26 simulation tool and validated. This work shows better results than the compared ones in terms of validation metrics such as throughput (26%), encryption time (19%), decryption time (16%), response time (15%), block validation time (31%), attack detection rate (16%), access control precision (13%), and scalability (28%).     

雾计算中支持计算外包的微型属性加密方案

密文策略属性加密为基于云存储的物联网系统提供了一对多的访问控制,然而现有方案中存在开销大、粒度粗等问题.基于此,结合雾计算技术提出了一种支持计算外包的微型属性加密方案.该方案缩短了密钥与密文的长度,减少了客户端的存储开销;将部分计算转载到雾节点,提高了加解密效率;具有更加丰富的策略表达能力,并且可以快速验证外包解密的正...     

基于可搜索加密机制的数据库加密方案

近年来,数据外包的日益普及引发了数据泄露的问题,云服务器要确保存储的数据具有足够的安全性,为了解决这一问题,亟需设计一套高效可行的数据库加密方案,可搜索加密技术可较好地解决面向非结构文件的查询加密问题,但是仍未较好地应用在数据库中,因此,针对上述问题,提出基于可搜索加密机制的数据库加密方案.本文贡献如下:第一,构造完整的密态数据库查询框架,保证了数据的安全性且支持在加密的数据库上进行高效的查询;第二,提出了满足IND-CKA1安全的数据库加密方案,在支持多种查询语句的前提下,保证数据不会被泄露,同时在查询期间不会降低数据库中的密文的安全性;第三,本方案具有可移植性,可以适配目前主流的数据库如MySQL、PostgreSQL等,本文基于可搜索加密方案中安全索引的构建思想,利用非确定性加密方案和保序加密方案构建密态数据库安全索引结构,利用同态加密以及AES-CBC密码技术对数据库中的数据进行加密,实现丰富的SQL查询,包括等值查询、布尔查询、聚合查询、范围查询以及排序查询等,本方案较BlindSeer在功能性方面增加了聚合查询的支持,本方案改善了CryptDB方案执行完成SQL查询后产生相等性泄露和顺序泄露的安全性问题,既保证了数据库中密文的安全性,又保证了系统的可用性,最后,我们使用一个有10000条记录的Student表进行实验,验证了方案框架以及算法的有效性,同时,将本方案与同类方案进行功能和安全性比较,结果表明本方案在安全性和功能性之间取得了很好的平衡.     

区块链赋能的高效物联网数据激励共享方案

近年来,随着大量设备不断地加入物联网中,数据共享作为物联网市场的主要驱动因素成为了研究热点.然而,当前的物联网数据共享存在着出于安全顾虑和缺乏激励机制等原因导致用户不愿意参与共享数据的问题.在此背景下,区块链技术为解决用户的信任问题和提供安全的数据存储被引入到物联网数据共享中.然而在构建基于区块链的安全分布式数据共享系统的探索中,如何突破区块链固有的性能瓶颈仍然是一个关键挑战.为此,本文研究了基于区块链的高效物联网数据激励共享方案.该方案首先提出了一个高效的区块链物联网数据激励共享框架,称为ShareBC.ShareBC利用分片技术构建能够并行处理数据共享交易的异步共识区,并在云/边缘服务器上和分片异步共识区上部署高效的共识机制,从而提高数据共享交易的处理效率.然后,为激励物联网用户参与数据共享,提出了一种基于智能合约实现的层次数据拍卖模型的共享激励机制.该机制解决了物联网数据共享中涉及的多层数据分配有效性问题,能够最大限度地提高整体社会福利.最后,实验结果证明了该方案的经济效益、激励兼容性和实时性以及可扩展性,且具有较低的计算成本和良好的实用性.     

面向便携式诊所的安全数据共享方案

随着物联网(Internet of Things, IoT)、云计算等技术的飞速发展, 便携式诊所(portable health clinic, PHC)得以实现, 并广泛应用于远程医疗. 我国依托5G通信的大幅优势, 积极推进智慧医疗的建设, 搭建了多功能、高质量的远程医疗信息服务平台. 以PHC为代表的远程医疗得以实现, 离不开远程数据共享系统的技术支撑. 目前IoT和云服务器(cloud server, CS)相结合(通常称为云边协同)的远程数据共享系统以其灵活性、高效性广受关注, 然而其隐私和安全问题却鲜有研究. 考虑到医疗数据的敏感性, 致力于研究PHC数据共享系统的安全隐私问题, 实现PHC系统中物联网感知数据的安全上传、个性密文的归一化、云服务器上动态多用户的细粒度访问控制、高效的解密操作, 并给出形式化的安全性证明. 在具体创新上, 第一, 分别对经典的代理重加密和属性基加密算法进行改进, 提出IPRE-TO-FAME组合加密机制, 以保障云边协同的PHC系统数据共享的安全性. 第二, 为了应对物联网终端数量众多、分散性强带来的密钥更新难题, 借鉴代理重加密(proxy re-encryption, PRE)的思想, 实现基于单方变换的密钥更新, 即无需变换IoT终端密钥条件下的密钥更新. 同时, 应用场景中重加密方可视为完全可信, 而常规PRE机制重加密方通常为不可信的第三方服务器, 为此, 改进经典PRE算法, 提出一种高效的IPRE (improved PRE)算法, 以适应提出的场景; 第三, 改进经典的FAME (fast attribute-based message encryption)机制, 实现动态多用户的细粒度访问控制, 便于用户可以随时随地使用便携式智能设备访问数据. 安全性证明、理论分析和实验结果证明, 提出的方案具有较好的安全性和较强的实用性, 是一类解决PHC安全数据共享问题的有效方案.     

基于DICE的证明存储方案

信息技术的不断发展和智能终端设备的普及导致全球数据存储总量持续增长,数据面临的威胁挑战也随着其重要性的凸显而日益增加,但目前部分计算设备和存储设备仍存在缺乏数据保护模块或数据保护能力较弱的问题.现有数据安全存储技术一般通过加密的方式实现对数据的保护,但是数据的加解密操作即数据保护过程通常都在应用设备上执行,导致应用设备遭受各类攻击时会对存储数据的安全造成威胁.针对以上问题,本文提出了一种基于DICE的物联网设备证明存储方案,利用基于轻量级信任根DICE构建的可信物联网设备为通用计算设备(统称为主机)提供安全存储服务,将数据的加解密操作移至可信物联网设备上执行,消除因主机遭受内存攻击等风险对存储数据造成的威胁.本文工作主要包括以下3方面:(1)利用信任根DICE构建可信物联网设备,为提供可信服务提供安全前提.(2)建立基于信任根DICE的远程证明机制和访问控制机制实现安全认证和安全通信信道的建立.(3)最终利用可信物联网设备为合法主机用户提供可信的安全存储服务,在实现数据安全存储的同时,兼顾隔离性和使用过程的灵活性.实验结果表明,本方案提供的安全存储服务具有较高的文件传输速率,并具备较高...     

基于CP-ABE和XACML多权限安全云存储访问控制方案

为了保护云存储系统中用户数据的机密性和用户隐私,提出了一种基于属性加密结合XACML框架的多权限安全云存储访问控制方案。通过CP-ABE加密来保证用户数据的机密性,通过XACML框架实现基于属性细粒度访问控制。云存储系统中的用户数据通过对称加密机制进行加密,对称密钥采用CP-ABE加密。仿真实验表明,该方案是高效灵活并且安全的。安全性分析表明,该方案能够抵抗共谋攻击,具有数据机密性以及后向前向保密性。     

An efficient PHR service system supporting fuzzy keyword search and fine-grained access control

Outsourcing of personal health record (PHR) has attracted considerable interest recently. It can not only bring much convenience to patients, it also allows efficient sharing of medical information among researchers. As the medical data in PHR is sensitive, it has to be encrypted before outsourcing. To achieve fine-grained access control over the encrypted PHR data becomes a challenging problem. In this paper, we provide an affirmative solution to this problem. We propose a novel PHR service system which supports efficient searching and fine-grained access control for PHR data in a hybrid cloud environment, where a private cloud is used to assist the user to interact with the public cloud for processing PHR data. In our proposed solution, we make use of attribute-based encryption (ABE) technique to obtain fine-grained access control for PHR data. In order to protect the privacy of PHR owners, our ABE is anonymous. That is, it can hide the access policy information in ciphertexts. Meanwhile, our solution can also allow efficient fuzzy search over PHR data, which can greatly improve the system usability. We also provide security analysis to show that the proposed solution is secure and privacy-preserving. The experimental results demonstrate the efficiency of the proposed scheme.     

Memory leakage-resilient searchable symmetric encryption

Along with the popularization and rapid development of cloud-computing, more and more individuals and enterprises choose to store their data in cloud servers. However, in order to protect data privacy and deter illegal accesses, the data owner has to encrypt his data before outsourcing it to the cloud server. In this situation, searchable encryption, especially searchable symmetric encryption (SSE) has become one of the most important techniques in cloud-computing area. In the last few years, researchers have presented many secure and efficient SSE schemes. Like traditional encryption, the security of all existing SSE schemes are based on the assumption that the data owner holds a secret key that is unknown to the adversary. Unfortunately, in practice, attackers are often able to obtain some or even all of the data owner’s secret keys by a great variety of inexpensive and fast side channel attacks. Facing such attacks, all existing SSE schemes are no longer secure. In this paper, we investigate how to construct secure SSE schemes with the presence of memory attack. We firstly propose the formal definition of memory leakage-resilient searchable symmetric encryption (MLR-SSE, for short). Based on that, we present one adaptive MLR-SSE scheme and one efficient non-adaptive dynamic MLR-SSE scheme based on physical unclonable functions (PUFs), and formally prove their security in terms of our security definitions.     

云计算中基于属性和定长密文的访问控制方法

随着云计算应用的增加,安全问题引起了人们的高度重视。由于云计算环境的分布式和不可信等特征,数据属主有时需要对数据加密后再托管云存储,如何实现非可信环境中加密数据的访问控制是云计算技术和应用需要解决的问题。文中提出一种基于属性和固定密文长度的层次化访问控制方法,该方案将密文长度和双线性对计算量限制在固定值,具有较高的效率,并且引入层次化授权结构,减少了单一授权的负担和风险,实现了高效、精细、可扩展的访问控制。同时证明了该方案在判定性q-BDHE假设下具有CCA2安全性。     

VMKDO: Verifiable multi-keyword search over encrypted cloud data for dynamic data-owner

The advantages of cloud computing encourage individuals and enterprises to outsource their local data storage and computation to cloud server, however, data security and privacy concerns seriously hinder the practicability of cloud storage. Although searchable encryption (SE) technique enables cloud server to provide fundamental encrypted data retrieval services for data-owners, equipping with a result verification mechanism is still of prime importance in practice as semi-trusted cloud server may return incorrect search results. Besides, single keyword search inevitably incurs many irrelevant results which result in waste of bandwidth and computation resources. In this paper, we are among the first to tackle the problems of data-owner updating and result verification simultaneously. To this end, we devise an efficient cryptographic primitive called as verifiable multi-keyword search over encrypted cloud data for dynamic data-owner scheme to protect both data confidentiality and integrity. Rigorous security analysis proves that our scheme is secure against keyword guessing attack (KGA) in standard model. As a further contribution, the empirical experiments over real-world dataset show that our scheme is efficient and feasible in practical applications.     

A secure authentication scheme based on elliptic curve cryptography for IoT and cloud servers

The Internet of Things (IoT) is now a buzzword for Internet connectivity which extends to embedded devices, sensors and other objects connected to the Internet. Rapid development of this technology has led to the usage of various embedded devices in our daily life. However, for resource sharing and communication among these devices, there is a requirement for connecting these embedded devices to a large pool of resources like a cloud. The promising applications of IoT in Government and commercial sectors are possible by integrating cloud servers with these embedded devices. But such an integration of technologies involves security issues like data privacy and authentication of devices whenever information is exchanged between them. Recently, Kalra and Sood proposed an authentication scheme based on elliptic curve cryptography (ECC) for IoT and cloud servers and claimed that their scheme satisfies all security requirements and is immune to various types of attacks. However, in this paper, we show that Kalra and Sood scheme is susceptible to offline password guessing and insider attacks and it does not achieve device anonymity, session key agreement, and mutual authentication. Keeping in view of the shortcomings of Kalra and Sood’s scheme, we have proposed an authentication scheme based on ECC for IoT and cloud servers. In the proposed scheme in this paper, we have formally analyzed the security properties of the designed scheme by the most widely accepted and used Automated Validation of Internet Security Protocols and Applications tool. Security and performance analysis show that when compared with other related schemes, the proposed scheme is more powerful, efficient, and secure with respect to various known attacks.     

A secure cloud-assisted urban data sharing framework for ubiquitous-cities

With the accelerated process of urbanization, more and more people tend to live in cities. In order to deal with the big data that are generated by citizens and public city departments, new information and communication technologies are utilized to process the urban data, which makes it more easier to manage. Cloud computing is a novel computation technology. After cloud computing was commercialized, there have been lot of cloud-based applications. Since the cloud service is provided by the third party, the cloud is semi-trusted. Due to the features of cloud computing, there are many security issues in cloud computing. Attribute-based encryption (ABE) is a promising cryptography technique which can be used in the cloud to solve many security issues. In this paper, we propose a framework for urban data sharing by exploiting the attribute-based cryptography. In order to fit the real world ubiquitous-cities utilization, we extend our scheme to support dynamic operations. In particular, from the part of performance analysis, it can be concluded that our scheme is secure and can resist possible attacks. Moreover, experimental results and comparisons show that our scheme is more efficient in terms of computation.     

一种隐藏访问结构的文件层次属性加密研究

基于文件层次结构的属性加密方案在云存储环境下是高效率、低存储的,但访问结构本身包含敏感信息,存在用户信息泄露、文件易被窃取的风险,针对这一问题提出了一种隐藏访问结构的文件层次属性加密方案。该方案在不影响加密解密效率的前提下提高了加密算法的安全性,并采用双因子身份认证机制实现了更安全高效的访问控制。该研究成果基于判定性双线性Diffie-Hellman假设,在标准模型下被证明是安全的。     

Sharing your privileges securely: a key-insulated attribute based proxy re-encryption scheme for IoT

Attribute based proxy re-encryption (ABPRE) combines the merits of proxy re-encryption and attribute based encryption, which allows a delegator to re-encrypt the ciphertext according to the delegatees’ attributes. The theoretical foundations of ABPRE has been well studied, yet to date there are still issues in schemes of ABPRE, among which time-bounded security and key exposure protection for the re-encryption keys are the most concerning ones. Within the current ABPRE framework, the re-encryption keys are generated independently of the system time segments and the forward security protection is not guaranteed when the users’ access privileges are altered. In this paper, we present a key-insulated ABPRE scheme for IoT scenario. We realize secure and fine-grained data sharing by utilizing attribute based encryption over the encrypted data, as well as adopting key-insulation mechanism to provide forward security for re-encryption keys and private keys of users. In particular, the lifetime of the system is divided into several time slices, and when system enters into a new slice, the user’s private keys need are required to be refreshed. Therefore, the users’ access privileges in our system are time-bounded, and both re-encryption keys and private keys can be protected, which will enhance the security level during data re-encryption, especially in situations when key exposure or privilege alternation happens. Our scheme is proved to be secure under MDBDH hardness assumptions as well as against collusion attack. In addition, the public parameters do not have to be changed during the evolution of users’ private keys, which will require less computation resources brought by parameter synchronization in IoT.     

对象云存储中分类分级数据的访问控制方法

随着云计算技术的广泛应用,云存储中数据的安全性、易管理性面临着新的挑战.对象云存储系统是一种新型的数据存储云计算体系结构,通常用来存储具有分类分级特点的非结构化数据.在云服务不可信的前提下,如何实现对云存储中大量具有分类分级特点资源的细粒度访问控制机制,保障云存储中数据不被非法访问是云计算技术中亟需解决的问题.对近些年来国内外学者的成果进行研究,发现现有的方案并不能有效应对这种新问题.本文利用强制访问控制、属性基加密、对象存储各自的优势,并结合分类分级的属性特点,提出了一个基于安全标记对象存储访问控制模型.同时给出了CGAC算法和其安全证明,将分类分级特点的属性层级支配关系嵌入ABE机制中,生成固定长度的密文.该算法不仅访问控制策略灵活,具有层次化授权结构,还可以友好的与对象存储元数据管理机制结合.通过理论效率分析和实验系统实现,验证了所提出方案计算、通信开销都相对较小,具有很高的实际意义.     

Hadoop环境中基于属性和定长密文的访问控制方法

随着云计算技术的广泛应用,人们越来越关注安全和隐私问题。由于云端是第三方服务器,并非完全可信,数据属主需要将数据加密后再托管云存储。如何实现对加密数据的高效访问控制是云计算技术亟需解决的问题。结合Hadoop云平台、基于属性与固定密文长度的加密方案提出并实现了一种在Hadoop云环境下基于属性和固定密文长度的层次化访问控制模型。该模型不仅具有固定密文长度、层次化授权结构、减少双线性对计算量的特点;同时经过实验验证,该模型能够实现云计算环境下对加密数据的高效访问控制,并解决了云存储空间有限的问题。