一个支持错误定位的批处理数据拥有性证明方案

数据拥有性证明技术是当前云存储安全领域中的一大重要研究内容,目的是不必下载所有文件,就能安全而高效地远程校验存储在云服务器中的数据是否完整.目前已陆续提出了许多批处理数据拥有性证明方案,但大多数方案都没有考虑用户数据出错后的错误定位问题,仅有的几个批处理校验方案也只能单独定位错误数据所在服务器或其所属用户.提出了利用定位标签辅助第三方审计员快速定位错误的方法,并在Zhou等人工作的基础上,利用Merkle Hash Tree构造数据定位标签,实现了一个多用户、多服务器环境下支持批处理校验且具备错误数据定位功能的数据拥有性证明方案,可以在批处理校验失败后快速定位错误数据的拥有者和所在服务器.在随机谕言机模型下,该方案是可证明安全的,且性能分析表明,定位错误数据的能力和效率比其他具有单一定位功能的方案更高.     

多云存储中保护隐私的数据完整性验证方案

随着云存储的应用,越来越多的用户选择将数据分散地存储在多个云服务器上,但是这种远程存储方式给用户数据的完整性带来了挑战。同时,代替用户校验数据完整性的第三方审计（TPA）近来也被指出存在泄露用户数据隐私的风险。针对现有的远程数据安全性、隐私性及高效验证的问题,提出一种多用户多服务器环境下支持隐私保护的批处理数据完整性验证方案。方案在一般群模型和随机谕言机模型下是可证明安全的。性能分析和实验表明,与其他在多用户多服务器环境下拓展并保护隐私的方案相比,该方案具有较低的通信复杂度和计算复杂度。     

云存储服务中数据完整性审计方案综述

云存储是由云计算提供的一个重要服务,允许数据拥有者将数据远程存储到云服务器上,同时又能够从云服务器上便捷、高效地获取这些数据,没有本地存储和维护数据的负担。然而,这种新的数据存储模式也引发了众多安全问题,一个重要的问题就是如何确保云服务器中数据拥有者数据的完整性。因此,数据拥有者以及云存储服务提供商亟需一个稳定、安全、可信的完整性审计方案,用于审核云服务器中数据的完整性和可用性。不仅如此,一个好的数据完整性审计方案还需满足如下功能需求：支持数据的动态操作,包括插入、删除、修改;支持多用户、多云服务器的批量审计;确保用户数据的隐私性;注重方案的执行效率,尽量减少数据拥有者和云服务器的计算开销与通信开销。为了促进云存储服务的广泛应用与推广,文章重点对云数据完整性审计方案的研究现状进行综述,描述云存储以及数据完整性审计的相关概念、特点,提出云计算环境下数据完整性审计模型和安全需求,阐述云存储数据完整性审计的研究现状,并重点分析部分经典方案,通过方案对比,指出当前方案存在的优点及缺陷。同时,文章还指出了本领域未来的研究方向。     

基于GlusterFS的分布式数据完整性验证系统

云存储为用户提供了弹性而可靠的数据存储方案,使得用户可以在任何时刻通过网络访问云服务器存取数据,大大降低了用户自己维护数据的成本,但也引发了一系列安全问题。对于云存储而言,采取审计措施用于检查数据的完整性至关重要,但已有的大多数云数据完整性审计机制只是通过模拟实验证明了方案具有高效性,并未结合具体云存储场景进行分析实验。针对上述问题,文章结合GlusterFS分布式文件系统与BLS短签名机制设计了一种分布式并行数据审计方案。利用GlusterFS的多个存储节点并行计算数据块所对应的标签,通过验证数据块对应标签的完整性来验证数据块的完整性,实现数据的单块审计、多块审计、多用户审计和异步审计,且不会泄露用户的隐私信息。此外,还进行了安全性分析。实验结果表明,文章方案可实现多块数据的高效并行审计,且并发量随节点的增加而线性增长。     

基于Paillier加密的数据多副本持有性验证方案

云存储服务中,用户将数据存储在不可信的云储存服务器上,为检查云存储中服务提供商(CSP)是否按协议完整地存储了用户的所有数据副本,提出一种 支持对数据副本进行动态操作 的基于Paillier加密的数据多副本持有性验证方案, 即DMR-PDP方案。该方案为实现多副本检查,将文件块以文件副本形式存储在云服务器上,将各副本编号与文件连接后利用Paillier密码系统生成副本文件以防止CSP各服务器的合谋攻击。利用BLS签名实现对所有副本的批量验证。将文件标志和块位置信息添加到数据块标签中,以保证本方案的安全性,支持对文件的动态更新操作。安全性分析和仿真实验结果表明,该方案在安全性、通信和计算开销方面的性能优于其他文献提出的方案,极大地提高了文件存储和验证的效率,减少了计算开销。     

云存储环境下基于身份的分布式数据持有型验证算法研究

云存储中,对远程数据的完整性验证是至关重要的。用户可以在不需要下载全部数据的情况下,验证存在云服务器中的数据是否完整。在某些应用场景中,用户需要存储他们的数据在多云服务器上,同时,为了减少验证的开销,验证检测算法必须是高效的。针对这种情况,提出一种新的远程数据完整性检测模型:在多云环境下,基于身份的分布式数据持有型验证,即ID-DPDP模型。此外,通过与其他方案进行对比分析,证明所提出方案是安全的、高效的。     

基于同态加密的多关键词检索方案

随着云存储服务的发展,越来越多的数据拥有者选择将数据外包给云服务商存储。为了保证数据的安全性,云服务器上的数据应该以密文形式存储。现有的多关键词密文检索技术不能兼顾准确性和安全性的问题,提出一种利用改进的向量空间模型和同态加密技术进行多关键词检索的方案。性能分析表明该方案能够有效地解决密文的多关键词检索问题。     

支持隐私保护和公平支付的数据完整性验证方案

随着云存储模式的出现,越来越多的数据拥有者(data owner, DO)选择将数据移植到云中,为了确保DO存储在云中数据的完整性,DO通常采用云存储数据完整性验证模型.在按需付费的云环境下,DO除了需要支付费用给云服务提供商外,还需要支付额外费用给第三方验证者(third party auditor, TPA)用于执行验证操作.然而,在实际的完整性验证中,TPA并不完全可信.为解决TPA不可信问题并且实现服务-支付公平,提出一种支持隐私保护和公平支付的数据完整性验证方案.首先,引入一种新型数据认证结构——基于等级的Merkle散列树,以实现数据位置的完整性验证和数据的可验证动态更新;其次,为实现数据隐私保护并减少通信开销,提出无交互式动态数据完整性证明机制(non-interactive dynamic provable data possession, NIDPDP);最后,结合区块链技术,利用智能合约(smart contract, SC)实现DO、云存储服务器(cloud storage server, CSS)和TPA之间的服务-支付公平,使各方诚实地按照规则执行.性能分析与...     

面向云存储的多副本文件完整性验证方案

文件完整性验证是云存储服务的一项重要安全需求.研究者已经提出多项针对云存储文件完整性验证的机制,例如数据持有性验证(prove of data possession,PDP)或者数据可恢复证明(proof of retrievability,POR)机制.但是,现有方案只能够证明远程云存储持有一份正确的数据,不能检验其是否保存多份冗余存储.在云存储场景中,用户需要验证云存储确实持有一定副本数的正确文件,以防止部分文件意外损坏时无法通过正确的副本进行恢复.提出的多副本文件完整性验证方案,能够帮助用户确定服务器正确持有的文件副本数目,并能够定位出错的文件块位置,从而指导用户进行数据恢复.实验证明,充分利用了多服务器分布式计算的优势,在验证效率上优于单副本验证方案.     

云存储中基于MHT的动态数据完整性验证与恢复方案

针对云服务器上存储数据完整性验证过程中的高通信开销和动态数据验证问题,提出一种基于Merkle哈希树(MHT)的动态数据完整性验证与恢复方案。首先,基于MHT构建了一种新型分层认证数据结构,将数据块的每个副本块组织成副本子树,以此大幅降低多副本更新验证的通信开销。然后,在数据验证中,融入了对服务器安全索引信息的认证,以此避免服务器攻击。最后,当发现数据损坏时,通过二分查找和Shamir秘密共享机制来恢复数据。实验结果表明,该方案在验证过程中能有效降低计算和通讯开销,并能够很好地支持数据的动态操作。     

VKSE-MO: verifiable keyword search over encrypted data in multi-owner settings

Searchable encryption (SE) techniques allow cloud clients to easily store data and search encrypted data in a privacy-preserving manner, where most of SE schemes treat the cloud server as honest-but-curious. However, in practice, the cloud server is a semi-honest-but-curious third-party, which only executes a fraction of search operations and returns a fraction of false search results to save its computational and bandwidth resources. Thus, it is important to provide a results verification method to guarantee the correctness of the search results. Existing SE schemes allow multiple data owners to upload different records to the cloud server, but these schemes have very high computational and storage overheads when applied in a different but more practical setting where each record is co-owned by multiple data owners. To address this problem, we develop a verifiable keyword search over encrypted data in multi-owner settings (VKSE-MO) scheme by exploiting the multisignatures technique. Thus, our scheme only requires a single index for each record and data users are assured of the correctness of the search results in challenging settings. Our formal security analysis proved that the VKSE-MO scheme is secure against a chosen-keyword attack under a random oracle model. In addition, our empirical study using a real-world dataset demonstrated the efficiency and feasibility of the proposed scheme in practice.     

基于数据持有性证明的完整性验证技术综述

在云存储环境中,为确保用户数据的完整性和可用性,用户需要对存储在云服务器中的数据进行完整性验证。现有的数据完整性验证机制主要有两种：数据持有性证明（Provable Data Possession,PDP）与可恢复数据证明（Proof of Retrievability,POR）。重点讨论了基于PDP的云存储数据完整性验证机制。结合PDP验证机制特性,对PDP方案进行分类,并总结了各分类使用的关键技术;根据分类阐述了PDP方案的研究现状,并对典型方案在动态验证、批量审计、计算开销等几个方面进行了对比分析;讨论了基于PDP的云存储数据完整性验证机制未来的发展方向。     

Secure multi-server-aided data deduplication in cloud computing

Cloud computing enables on-demand and ubiquitous access to a centralized pool of configurable resources such as networks, applications, and services. This makes that huge of enterprises and individual users outsource their data into the cloud server. As a result, the data volume in the cloud server is growing extremely fast. How to efficiently manage the ever-increasing datum is a new security challenge in cloud computing. Recently, secure deduplication techniques have attracted considerable interests in the both academic and industrial communities. It can not only provide the optimal usage of the storage and network bandwidth resources of cloud storage providers, but also reduce the storage cost of users. Although convergent encryption has been extensively adopted for secure deduplication, it inevitably suffers from the off-line brute-force dictionary attacks since the message usually can be predictable in practice. In order to address the above weakness, the notion of DupLESS was proposed in which the user can generate the convergent key with the help of a key server. We argue that the DupLESS does not work when the key server is corrupted by the cloud server. In this paper, we propose a new multi-server-aided deduplication scheme based on the threshold blind signature, which can effectively resist the collusion attack between the cloud server and multiple key servers. Furthermore, we prove that our construction can achieve the desired security properties.     

Efficient integrity verification of replicated data in cloud using homomorphic encryption

The cloud computing is an emerging model in which computing infrastructure resources are provided as a service over the internet. Data owners can outsource their data by remotely storing them in the cloud and enjoy on-demand high quality services from a shared pool of configurable computing resources. However, since data owners and the cloud servers are not in the same trusted domain, the outsourced data may be at risk as the cloud server may no longer be fully trusted. Therefore, data confidentiality, availability and integrity is of critical importance in such a scenario. The data owner encrypts data before storing it on the cloud to ensure data confidentiality. Cloud should let the owners or a trusted third party to check for the integrity of their data storage without demanding a local copy of the data. Owners often replicate their data on the cloud servers across multiple data centers to provide a higher level of scalability, availability, and durability. When the data owners ask the cloud service provider (CSP) to replicate data, they are charged a higher storage fee by the CSP. Therefore, the data owners need to be strongly convinced that the CSP is storing data copies agreed on in the service level contract, and data-updates have been correctly executed on all the remotely stored copies. To deal with such problems, previous multi copy verification schemes either focused on static files or incurred huge update costs in a dynamic file scenario. In this paper, we propose a dynamic multi-replica provable data possession scheme (DMR-PDP) that while maintaining data confidentiality prevents the CSP from cheating, by maintaining fewer copies than paid for and/or tampering data. In addition, we also extend the scheme to support a basic file versioning system where only the difference between the original file and the updated file is propagated rather than the propagation of operations for privacy reasons. DMR-PDP also supports efficient dynamic operations like block modification, insertion and deletion on replicas over the cloud servers. Through security analysis and experimental results, we demonstrate that the proposed scheme is secure and performs better than some other related ideas published recently.     

Approaches and challenges of privacy preserving search over encrypted data

More and more data owners are encouraged to outsource their data onto cloud servers for reducing infrastructure, maintenance cost and also to get ubiquitous access to their stored data. However, security is one issue that discourages data owners from adopting cloud servers for data storage. Searchable Encryption (SE) is one of the few ways of assuring privacy and confidentiality of such data by storing them in encrypted form at the cloud servers. SE enables the data owners and users to search over encrypted data through trapdoors. Most of the user information requirements are fulfilled either through Boolean or Ranked search approaches. This paper aims at understanding how the confidentiality and privacy of information can be guaranteed while processing single and multi-keyword queries over encrypted data using Boolean and Ranked search approaches. This paper presents all possible leakages that happen in SE and also specifies which privacy preserving approach to be adopted in SE schemes to prevent those leakages to help the practitioners and researchers to design and implement secure searchable encryption systems. It also highlights various application scenarios where SE could be utilized. This paper also explores the research challenges and open problems that need to be focused in future.     

Efficient data integrity auditing for storage security in mobile health cloud

Cloud storage services can enable data owners to eliminate the need for the initial investment of expensive infrastructure setup and also minimize development and maintenance costs. Outsourcing the health data to e-health cloud storage server is very beneficial. Nonetheless, storing the health data on cloud servers also brings serious security challenges. In this paper, we propose a highly efficient data integrity auditing scheme for cloud storage for mobile health applications. The authentication tag for each data block generated by biosensor nodes is minimal in our scheme due to the use of hash operation. Moreover, in data integrity checking phase, message-locked encryption scheme is utilized to encrypt and transport the auditing information of the checked data blocks, which significantly reduces the required amount of calculation and communication resources. Compared with the conventional third party auditing schemes, the presented scheme speeds up the tag generation and tag checking process by more than one thousand times.     

具有紧凑标签的基于身份匿名云审计方案

云存储技术具有效率高、可扩展性强等优点。用户可以借助云存储技术节省本地的存储开销,并与他人共享数据。然而,数据存储到云服务器后,用户失去对数据的物理控制,需要有相应的机制保证云中数据的完整性。数据拥有证明（PDP,provable data possession）机制允许用户或用户委托的第三方审计员（TPA,third party auditor）对数据完整性进行验证。但在实际应用中,数据通常由多个用户共同维护,用户在进行完整性验证请求的同时泄露了自己的身份。匿名云审计支持 TPA 在完成数据完整性验证时保证用户的匿名性。在基于身份体制下,匿名云审计方案通常需要借助基于身份的环签名或群签名技术实现,数据标签的构成元素与用户数量相关,使得数据标签不够紧凑,存储效率较低。为了解决这一问题,提出一种基于身份的匿名云审计方案通用构造,使用一个传统体制下的签名方案和一个传统体制下的匿名云审计方案即可构造一个基于身份的匿名云审计方案。基于该通用构造,使用 BLS 签名和一个传统体制下具有紧凑标签的匿名云审计方案设计了具有紧凑标签的基于身份匿名云审计方案。该方案主要优势在于数据标签短,能够减少云服务器的存储压力,提高存储效率。此外,证明了该方案的不可欺骗性和匿名性。