具有隐私保护的云存储访问控制方案

针对传统的访问控制方案无法在云计算环境下保护用户的属性隐私,提出了具有隐私保护的云存储访问控制方案。采用混合加密体制实现了数据的机密性,即利用对称密钥加密明文数据,再利用公钥密码体制对对称密钥进行加密。在新的访问控制方案中,公钥加密采用了匿名的密文策略下基于属性的加密技术。安全性分析表明,新方案在保护用户属性隐私的同时,达到了选择明文安全性,可抵抗恶意用户及云存储服务器的合谋攻击。     

保护用户隐私的数据加密与安全存储方案

文中提出了一套保护用户隐私的数据加密与安全存储方案,选择了适合的加密算法和密钥管理方案。通过对比分析不同加密算法的安全性和效率,最终选择了AES 256,RSA等加密算法,并设计了三级密钥管理方案,实现了对密钥的安全存储和分发。在数据存储方面,以eMMC存储器为存储介质,实现了基于角色和权限的访问控制机制,确保用户只能访问其被授权的数据。     

基于授权的多服务器可搜索密文策略属性基加密方案

针对现有属性基可搜索加密方案缺乏对云服务器授权的服务问题,该文提出一种基于授权的可搜索密文策略属性基加密(CP-ABE)方案。方案通过云过滤服务器、云搜索服务器和云存储服务器协同合作实现搜索服务。用户可将生成的授权信息和陷门信息分别发送给云过滤服务器和云搜索服务器,在不解密密文的情况下,云过滤服务器可对所有密文进行检测。该方案利用多个属性授权机构,在保证数据机密性的前提下能进行高效的细粒度访问,解决数据用户密钥泄露问题,提高数据用户对云端数据的检索效率。通过安全性分析,证明方案在提供数据检索服务的同时无法窃取数据用户的敏感信息,且能够有效地防止数据隐私的泄露。     

面向云存储的安全密文访问控制方案

存储在云端服务器中的敏感数据的保密和安全访问是云存储安全研究的重要内容.针对真实的云存储环境中云服务提供商不可信的情况,采用基于属性的加密算法,提出了一种安全、高效、细粒度的云存储密文访问控制方案.与现有方案相比,该方案在用户撤销时,通过引入广播加密技术,使得撤销用户即使和云服务提供商共谋,也不能对私钥进行更新,保证了数据的安全性;方案将大部分密文重加密和用户私钥更新工作转移给云服务提供商执行,在保证安全性的前提下,降低了数据属主的计算代价;另外该方案还可支持多用户的同时撤销.最后分析了方案的安全性和计算复杂性,并测试了用户撤销时的运行效率.     

基于区块链的多授权密文策略属性基等值测试加密方案

针对云环境下密文策略属性基加密方案中存在的密文检索分类困难与依赖可信第三方等问题,本文提出了一种基于区块链的多授权密文策略属性基等值测试加密方案．利用基于属性的等值测试技术,实现了支持属性级灵活授权的云端数据检索和分类机制,降低了数据用户对重复数据解密的计算开销．结合多授权属性基加密机制和区块链技术,实现了去中心化用户密钥生成．采用多属性授权机构联合分发密钥,有效抵抗用户和属性授权机构的合谋攻击．引入区块链和智能合约技术,消除了现有密文策略属性基密文等值测试方案中等值测试、数据存储与外包解密操作对可信云服务器的依赖．利用外包服务器执行部分解密计算,降低了用户本地的计算开销．将原始数据哈希和验证参数上传至区块链,保障外包服务器解密结果正确性和云端数据完整性．在随机预言模型下,基于判定性qparallel Bilinear Diffie-Hellman Exponent困难问题证明了本文方案在选择密文攻击下的单向性．与同类方案相比较,本文方案支持更多的安全属性,并具有较低的计算开销．     

基于属性加密的云存储方案研究

云存储中往往采用属性加密方案来实现细粒度的访问控制,为了进一步保护访问控制策略中的敏感信息,并解决授权中心单独为用户生成密钥而产生的密钥托管问题。该文对访问控制策略中的属性进行重新映射,以实现其隐私性。另外在密钥生成算法中设计一个双方计算协议,由用户产生密钥的部分组件,与授权中心共同生成密钥以解决密钥托管问题。最后在标准模型下对方案进行了安全证明,并进行了性能分析与实验验证,实验结果表明,与已有相关方案相比,虽然为了实现访问控制策略隐藏并且解决密钥托管问题增加了额外的计算负载, 但是由于该文将大部分解密工作授权给云存储中心来执行,因此数据访问者的计算负载较小。     

面向移动云计算的多要素代理重加密方案

云与移动计算的融合使用户能够更方便快捷地获取数据和服务,但是由于云平台和移动通信网络的开放性,如何在移动云计算环境下实现数据安全的访问和使用成为了亟待解决的问题。设计了一种基于多要素访问控制条件的代理重加密方案,包含系统模型、重加密算法及重加密密钥描述方法。基于该方案,云计算数据中心通过移动用户的访问请求,获取用户的客观访问控制条件,为用户生成相应的重加密密文,用户使用自身私钥即可对授权数据解密。在不增加用户密钥管理量的前提下,实现了移动云计算的多要素代理重加密。     

云存储环境下多服务器的密钥聚合可搜索加密方案

密钥聚合可搜索加密不仅可以通过关键字检索密文,还可以减少用户密钥管理的代价和安全风险。该文分析了一个可验证的密钥聚合可搜索加密方案,指出该方案不满足关键字猜测攻击,未经授权的内部用户可以猜测其他用户的私钥。为了提高原方案的安全性,提出了云存储环境下多服务器的密钥聚合可搜索加密方案。所提方案不仅改进了原方案的安全性问题,还增加了多服务的特性,提高了上传和存储的效率,更适合一对多的用户环境。     

基于云计算的计算机信息安全技术分析

随着云计算技术的快速发展和广泛应用,数据安全、隐私保护和访问控制方面的信息安全需求和挑战,成为云服务提供商和用户面临的主要问题。针对该问题,文中提出了基于云计算的信息安全策略和技术,包括先进的数据加密方法、强化的身份认证机制、精细化的访问控制策略以及基于云环境的入侵检测和防御系统,旨在全面提升云计算环境中的数据保护和系统安全性。实验结果表明,该安全策略和技术在云计算环境中提高了数据保护水平和系统安全性,降低了安全威胁和风险,增强了整个云服务体系的安全性和用户信任度。     

支持临时解密授权的密文策略属性加密方案

属性加密是在云环境下实现细粒度访问控制的有效工具,但同类方案并未较好地解决数据所有者的隐私保护和解密权限临时授权问题。文章将属性代理重加密技术与Nishide等的属性加密方案相结合,提出同时支持访问策略隐藏和解密权限临时授权的密文策略属性加密方案。此外,文章利用新方案解决了医疗云环境下属性访问控制系统的构造问题。安全性分析表明,新的属性加密方案并未破坏底层方案的安全性,而且不会向代理服务器泄露数据所有者的解密私钥。     

Secure and privacy-preserving DRM scheme using homomorphic encryption in cloud computing

Cloud computing provides a convenient way of content trading and sharing. In this paper, we propose a secure and privacy-preserving digital rights management （DRM） scheme using homomorphic encryption in cloud computing. We present an efficient digital rights management framework in cloud computing, which allows content provider to outsource encrypted contents to centralized content server and allows user to consume contents with the license issued by license server. Further, we provide a secure content key distribution scheme based on additive homomorphic probabilistic public key encryption and proxy re-encryption. The provided scheme prevents malicious employees of license server from issuing the license to unauthorized user. In addition, we achieve privacy preserving by allowing users to stay anonymous towards the key server and service provider. The analysis and comparison results indicate that the proposed scheme has high efficiency and security.     

云计算平台下基于属性加密的动态版权使用控制方案（英文）

In order to achieve fine-grained access control in cloud computing,existing digital rights management(DRM) schemes adopt attribute-based encryption as the main encryption primitive.However,these schemes suffer from inefficiency and cannot support dynamic updating of usage rights stored in the cloud.In this paper,we propose a novel DRM scheme with secure key management and dynamic usage control in cloud computing.We present a secure key management mechanism based on attribute-based encryption and proxy re-encryption.Only the users whose attributes satisfy the access policy of the encrypted content and who have effective usage rights can be able to recover the content encryption key and further decrypt the content.The attribute based mechanism allows the content provider to selectively provide fine-grained access control of contents among a set of users,and also enables the license server to implement immediate attribute and user revocation.Moreover,our scheme supports privacy-preserving dynamic usage control based on additive homomorphic encryption,which allows the license server in the cloud to update the users' usage rights dynamically without disclosing the plaintext.Extensive analytical results indicate that our proposed scheme is secure and efficient.     

新型通用格式多媒体数字版权管理系统设计与实现

针对多媒体内容的版权保护问题,设计一种新型通用格式多媒体数字版权管理模型,包括内容加密与打包、密钥管理、安全引擎、许可证管理与分发、DRM客户端和DRM管理等功能单元,该模型通过非结构化加密方法,克服了基于内容格式加密方法的局限性,实现对通用格式多媒体内容的保护。另外,采用许可证提取码作为下载许可证的凭证,解决许可证重新发行和转让的问题,并支持细粒度使用控制方式。基于此模型,实现了基于固定与移动融合业务的多媒体数字版权管理系统,并将其运用于数字消费领域,实验结果和实际运行表明该方案不影响多媒体质量,效率及安全性较高,在多媒体内容版权保护方面具有较好的实用性。     

Address Permutation for Privacy‐Preserving Searchable Symmetric Encryption

This paper proposes a privacy‐preserving database encryption scheme that provides access pattern hiding against a service provider. The proposed scheme uses a session key to permute indices of database records each time they are accessed. The proposed scheme can achieve access pattern hiding in situations in which an adversary cannot access the inside of the database directly, by separating the entity with an index table and data table and permuting both the index and position where the data are stored. Moreover, it is very efficient since only O(1) server computation and communication cost are required in terms of the number of the data stored. It can be applied to cloud computing, where the intermediate entities such as cloud computing service provider can violate the privacy of users or patients.     

Verifiable attribute-based searchable encryption scheme based on blockchain

For the problem that the shared decryption key lacks of fine-grained access control and the search results lacks of correctness verification under one-to-many search model,a verifiable attribute-based searchable encryption scheme based on blockchain was proposed.The ciphertext policy attribute-based encryption mechanism was used on the shared key to achieve fine-grained access control.Ethereum blockchain technology was combined to solve the problem of incorrect search results returned by the semi-honest and curious cloud server model,so it could prompt both the cloud server and the user to follow the rules of the contract honestly and achieved service-payment fairness between the user and the cloud server in the pay-per-use cloud environment.In addition,based on the irreversible modification of the blockchain,the cloud server was guaranteed to receive the service fee,and the user was assured to obtain the correct retrieval results without additional verification which reduced the computational overhead of the user.The security analysis shows that the scheme satisfies the semantic security against adaptive chosen keyword attack and can protect the privacy of users and the security of data.The performance comparison and experimental results show that the scheme has certain optimizations in security index generation,search token generation,retrieval efficiency and transaction quantity,so it is more suitable for one-to-many search scenarios such as smart medical.     

Cloud data secure deduplication scheme via role-based symmetric encryption

The rapid development of cloud computing and big data technology brings prople to enter the era of big data,more and more enterprises and individuals outsource their data to the cloud service providers.The explosive growth of data and data replicas as well as the increasing management overhead bring a big challenge to the cloud storage space.Meanwhile,some serious issues such as the privacy disclosure,authorized access,secure deduplication,rekeying and permission revocation should also be taken into account.In order to address these problems,a role-based symmetric encryption algorithm was proposed,which established a mapping relation between roles and role keys.Moreover,a secure deduplication scheme was proposed via role-based symmetric encryption to achieve both the privacy protection and the authorized deduplication under the hierarchical architecture in the cloud computing environment.Furthermore,in the proposed scheme,the group key agreement protocol was utilized to achieve rekeying and permission revocation.Finally,the security analysis shows that the proposed role-based symmetric encryption algorithm is provably secure under the standard model,and the deduplication scheme can meet the security requirements.The performance analysis and experimental results indicate that the proposed scheme is effective and efficient.     

Authenticated content distribution framework for digital rights management systems with smart card revocation

The growing features of multimedia distribution across multiple smart devices have attained significant attention of many industries and users. In this context, digital rights management (DRM) is the system, which tries to ensure authorized content distribution. For much diverse and productive research in content distribution, DRM is paying attention to provide a better DRM protocol according to current requirements. But the violation of copyright protection of digital content (video, audio, and secret documents) still has a significant issue of concern. Not only solely copyright protection but also stolen smart cards which keep the license and more specific information of a user is also an attentive concern of DRM users. In this paper, we introduced an authenticated key agreement protocol which maintains secure and authorized content distribution with successful smart card revocation. Moreover, the proposed scheme has simulated under AVISPA tool, which informally confirms the security of the protocol. The formal proof security is given in the random oracle model and then done the performance evaluation. The comparison with the relevant existing schemes shows the advantage of the proposed scheme. It identified that the proposed protocol achieves all the desirable security and performance attributes with valid smart card revocation.     

采用加密机制在云计算环境中进行访问控制

从数据的隐私角度来讲,公有云的服务提供商对用户来说是不可信的。为保障用户数据私密性,需要采用加密技术在云计算这种开放互联的环境中对托管数据进行访问控制。文中对广播加密机制和CPK组合公钥密码机制在云计算环境中的访问控制应用进行了探讨,并对这两种加密机制的主要理论基础——多项式插值法、多线性映射,以及ECC复合定理进行了介绍。通过加密技术的应用,为实现在云计算等不可信的空间安全存取敏感数据提供了一种研究思路。     

Dynamic searchable encryption with privacy protection for cloud computing

The dynamic searchable encryption schemes generate search tokens for the encrypted data on a cloud server periodically or on a demand. With such search tokens, a user can query the encrypted data whiles preserving the data's privacy; ie, the cloud server can retrieve the query results to the user but do not know the content of the encrypted data. A framework DSSE with Forward Privacy (dynamic symmetric searchable encryption [DSSE] with forward privacy), which consists of Internet of Things and Cloud storage, with the attributes of the searchable encryption and the privacy preserving are proposed. Compared with the known DSSE schemes, our approach supports the multiusers query. Furthermore, our approach successfully patched most of the security flaws related to the sensitive information's leakage in the DSSE schemes. Both security analysis and simulations show that our approach outperforms other DSSE schemes with respect to both effectiveness and efficiency.