Analysis and improvement on identity-based cloud data integrity verification scheme

Many individuals or businesses outsource their data to remote cloud.Cloud storage provides users the advantages of economic convenience,but data owners no longer physically control over the stored data,which introduces new security challenges,such as no security guarantees of integrity and privacy.The security of two identity-based cloud data integrity verification schemes by Zhang et al and Xu et al respectively are analysed.It shows that Zhang et al.’s scheme is subjected to secret key recovery attack for the cloud servers can recover user’s private key only utilizing stored data.And Xu et al.’s scheme cannot satisfy security requirements of soundness.Based on Xu et al.'s scheme,a modified identity-based cloud data integrity verification scheme is proposed.A comprehensive analysis shows the new scheme can provide the security requirements of soundness and privacy,and has the same communication overhead and computational cost as Xu et al.’s scheme.     

Integrity checking protocol with identity-based proxy signature in mobile cloud computing

Based on provable data possession(PDP)model,a more perfect data integrity checking model for mobile cloud computing was proposed,in which there was an additional proxy party with stronger computing power to help the mobile users to calculate the block tags.Furthermore,for the proposed model,an identity-based proxy signature PDP(IBPS-PDP)protocol was presented.By using identity-based signatures,the system did not need to manage public key certificates and further the users did not need to take the additional computations to verify the other’s certificates yet.Finally,the security of the proposed IBPS-PDP protocol is proved in the random oracle model.     

Cross-domain data cloud storage auditing scheme based on certificateless cryptography

With the development of Internet of things (IoT), more and more intelligent terminal devices outsource data to cloud servers (CSs). However, the CS is not fully trusted, and the heterogeneity among different domains makes it difficult for third-party auditor (TPA) to conduct an efficient integrity auditing of outsourced data. Therefore, the cross-domain data cloud storage auditing scheme based on certificateless cryptography is proposed, which can effectively avoid the big burden of certificate management or key escrow problems in identity-based cryptography. At the same time, TPA can effectively audit the integrity of outsourced data in different domains. Formal security proof and analysis show that the cloud storage auditing scheme satisfies the security and privacy requirements. Performance analysis demonstrates that the efficiency is acceptable.     

基于属性加密的高效密文去重和审计方案

针对当前支持去重的属性加密方案既不支持云存储数据审计,又不支持过期用户撤销,且去重搜索和用户解密效率较低的问题,该文提出一种支持高效去重和审计的属性加密方案。该方案引入了第3方审计者对云存储数据的完整性进行检验,利用代理辅助用户撤销机制对过期用户进行撤销,又提出高效去重搜索树技术来提高去重搜索效率,并通过代理解密机制辅助用户解密。安全性分析表明该方案通过采用混合云架构,在公有云达到IND-CPA安全性,在私有云达到PRV-CDA安全性。性能分析表明该方案的去重搜索效率更高,用户的解密计算量较小。     

一个改进的云存储数据完整性验证方案

在云计算环境中,客户将数据存储在不可信的云存储服务器上.如何在本地没有数据副本的情况下,高效地对客户存储的远程数据进行完整性验证是一个亟待解决的问题,针对此问题已相继提出一系列解决方案.提出已知证据伪造攻击的概念,即拥有一定数量证据的敌手可以伪造新的合法证据.指出已有的一些数据完整性验证方案无法抵抗已知证据伪造攻击.利用基于等级的认证跳表提出一个改进方案,该方案支持完全数据更新和公开审计.     

Provable data possession scheme based on public verification and private verification

More and more users choose to transfer their applications and data into the cloud.Data security is a key issue for cloud storage systems.To ensure the integrity and validity of the data stored in the cloud,provable data possession (PDP) scheme is particularly important.In order to verify whether the cloud storage service provider had stored the data of the user completely,a scheme on the basis of NRPDP (non-repudiable PDP) was improved and extended,and a data retention scheme based on public authentication and private authentication was proposed.The scheme can verify the trustworthiness of the service provider and the user in the cloud storage at the same time,which satisfies the non-repudiation of the verification.The theory proves the non-repudiation of the proposed scheme.The experiment proves that the efficiency of each stage is better than that of the existing single public verification method or private authentication method.     

支持策略隐藏且密文长度恒定的可搜索加密方案

属性加密体制是实现云存储中数据灵活访问控制的关键技术之一,但已有的属性加密方案存在密文存储开销过大和用户隐私泄露等问题,并且不能同时支持云端数据的公开审计。为了解决这些问题,该文提出一个新的可搜索属性加密方案,其安全性可归约到q-BDHE问题和CDH问题的困难性。该方案在支持关键词搜索的基础上,实现了密文长度恒定;引入策略隐藏思想,防止攻击者获取敏感信息,确保了用户的隐私性;通过数据公开审计机制,实现了云存储中数据的完整性验证。与已有的同类方案相比较,该方案有效地降低了数据的加密开销、关键词的搜索开销、密文的存储成本与解密开销,在云存储环境中具有较好的应用前景。     

基于消息认证函数的云端数据完整性检测方案

针对云计算中数据完整性问题,该文提出了一个新的交互式完整性检测方案.该方案通过构造一个I型完善Cartesian消息认证函数及其等效函数,在同步存储数据验证值的前提下,利用等效函数判定云端应答的消息认证值来检测完整性.分析结果表明,该方案在大数分解的困难性假设下能正确检测完整性,并且运行时仅需用户端常量的计算量、存储占用量和网络通信量,相比较现有方案,具有明显效率优势.     

一种NTRU格上基于身份全同态加密体制设计

全同态加密可以用来解决云计算环境中的隐私保护问题,然而现有体制具有系统参数大、效率低的缺点.针对现有攻击技术,首先设计了一种高效的NTRU格上的基于身份公钥加密体制,无需借助额外的安全性假设,具有更高的安全性和更小的系统参数.之后,基于近似特征向量技术,构造了一种高效的全同态加密转化方式.通过将以上两种方法结合,给出了一种高效的基于身份全同态加密体制.和现有体制相比,除了不需要计算密钥、实现了真正意义上的基于身份特性以外,还减小了密钥、密文尺寸,提高了计算和传输效率.     

Blockchain-based continuous data integrity checking protocol with zero-knowledge privacy protection

The cloud computing technology has emerged, developed, and matured in recent years, consequently commercializing remote outsourcing storage services. An increasing number of companies and individuals have chosen the cloud to store their data. However, accidents, such as cloud server downtime, cloud data loss, and accidental deletion, are serious issues for some applications that need to run around the clock. For some mission and business-critical applications, the continuous availability of outsourcing storage services is also necessary to protect users' outsourced data during downtime. Nevertheless, ensuring the continuous availability of data in public cloud data integrity auditing protocols leads to data privacy issues because auditors can obtain the data content of users by a sufficient number of storage proofs. Therefore, protecting data privacy is a burning issue. In addition, existing data integrity auditing schemes that rely on semi-trusted third-party auditors have several security problems, including single points of failure and performance bottlenecks. To deal with these issues, we propose herein a blockchain-based continuous data integrity checking protocol with zero-knowledge privacy protection. We realize a concrete construction by using a verifiable delay function with high efficiency and proof of retrievability, and prove the security of the proposal in a random oracle model. The proposed construction supports dynamic updates for the outsourced data. We also design smart contracts to ensure fairness among the parties involved. Finally, we implement the protocols, and the experimental results demonstrate the efficiency of the proposed protocol.     

A survey on blockchain-based integrity auditing for cloud data

With the rapid advancement of cloud computing, cloud storage services have developed rapidly. One issue that has attracted particular attention in such remote storage services is that cloud storage servers are not enough to reliably save and maintain data, which greatly affects users’ confidence in purchasing and consuming cloud storage services. Traditional data integrity auditing techniques for cloud data storage are centralized, which faces huge security risks due to single-point-of-failure and vulnerabilities of central auditing servers. Blockchain technology offers a new approach to this problem. Many researchers have endeavored to employ the blockchain for data integrity auditing. Based on the search of relevant papers, we found that existing literature lacks a thorough survey of blockchain-based integrity auditing for cloud data. In this paper, we make an in-depth survey on cloud data integrity auditing based on blockchain. Firstly, we cover essential basic knowledge of integrity auditing for cloud data and blockchain techniques. Then, we propose a series of requirements for evaluating existing Blockchain-based Data Integrity Auditing (BDIA) schemes. Furthermore, we provide a comprehensive review of existing BDIA schemes and evaluate them based on our proposed criteria. Finally, according to our completed review and analysis, we explore some open issues and suggest research directions worthy of further efforts in the future.     

An Authenticated Identity-Based Key Establishment and Encryption Scheme for Wireless Sensor Networks

1Introduction Wirelesscommunicationhasbeenahotissuesince1990.includingAdhocandwirelesssensornetworks,etc.Especially,WirelessSensorNetwork(WSN).Whichhasreceivedconsiderableattentionduringlast decade[1-2].Ithasbeendevelopedforawidevarietyof applications,inc…     

基于外包存储的数据完整性检验的研究

近年来,外包存储获得了越来越广泛的应用,与此同时其安全性问题也备受人们的关注。特别是它需要一个有效的机制确保用户存储在远方不可信服务器上的数据没有被篡改,这也就是数据的完整性检验。完整性检验是不可信外包存储服务的至关重要的方面。讲述了两种有效的数据完整性验证的机制,并进行了比较分析,最后归纳总结了各自的优缺点及适用情况。     

多用户环境下无证书认证可搜索加密方案

可搜索加密技术的提出使用户能够将数据加密后存储在云端,而且可以直接对密文数据进行检索。但现有的大部分可搜索加密方案都是单用户对单用户的模式,部分多用户环境下的可搜索加密方案是基于传统公钥密码或基于身份公钥密码系统,因此这类方案存在证书管理和密钥托管问题,且容易遭受内部关键词猜测攻击。该文结合公钥认证加密和代理重加密技术,提出一个高效的多用户环境下无证书认证可搜索加密方案。方案使用代理重加密技术对部分密文进行重加密处理,使得授权用户可以利用关键字生成陷门查询对应密文。在随机预言模型下,证明方案具有抵抗无证书公钥密码环境下两类攻击者的内部关键词猜测攻击的能力,且该方案的计算和通信效率优于同类方案。     

云存储下多用户协同访问控制方案

CP-ABE被认为是云存储下最适合的数据访问控制方法之一,但它仅适合用户分别读取或者分别修改不同数据的情况,而直接应用CP-ABE进行多用户协同数据访问时,会存在修改无序、密文文件大量冗余等问题。多用户协同访问云端数据时,应该在保证机密性、抗共谋的前提下控制合法用户有序地修改同一密文文件,同时云端尽可能减少密文文件副本。针对文件和文件逻辑分块,提出了2个多用户协同访问控制方案MCA-F和MCA-B。MCA-F满足单个数据文件作为最小控制粒度的访问控制需求,该方案采用层次加密结构,云服务器承担部分解密计算,以降低用户解密的计算代价;针对多用户同时写数据的访问控制,提出了对多个用户提交的暂存数据的管理方法。MCA-B用于文件的逻辑分块作为最小控制粒度的访问控制,该方案设计了文件的逻辑分块机制、基于索引矩阵的表示方法,提出了子数据掩码表示方法以描述多个用户对同一文件不同逻辑分块的写权限;MCA-B支持用户集合、文件逻辑分块结构的动态变化,而且数据的拥有者和修改者无需一直在线。与现有的方案相比,所提方案不仅具有云存储下多用户协同写数据的访问控制能力,而且读访问控制的用户端存储量和加解密计算量是较小的。     

支持条件身份匿名的云存储医疗数据轻量级完整性验证方案

医疗云存储服务是云计算技术的一个重要应用,同时外包医疗数据的完整性和用户的身份隐私保护已变得越来越重要。该文提出适用于无线医疗传感器网络的支持条件身份匿名的外包云存储医疗数据轻量级完整性验证方案。方案结合同态哈希函数设计了聚合签名,通过第三方审计者(TPA)对外包云存储医疗数据进行完整性验证,在TPA端存放审计辅助信息,利用同态哈希函数的同态性质将TPA端的计算优化为常量运算,大大降低了第三方审计者的计算开销,同时支持TPA对多个数据文件执行批量验证,其验证开销几乎是恒定的,与医疗数据文件的数量无关。方案有效防止了第三方审计者通过求解线性方程恢复原始医疗数据,并且设计了条件身份匿名算法,密钥生成中心(PKG)根据用户唯一标识的身份信息为用户生成匿名身份及对应的签名私钥。即使攻击者截获到用户传输的医疗数据,也无法获知拥有此数据的真实身份,有效避免了对公钥证书的复杂管理,同时使得密钥生成中心可以有效追踪医疗信息系统中具有恶意行为的用户。安全性分析与性能评估结果表明该方案能够安全高效地部署在云辅助无线医疗传感器网络。     

Secure Data Access and Sharing Scheme for Cloud Storage

Cloud storage is a new storage mode emerged along with the development of cloud computing paradigm. By migrating the data to cloud storage, the consumers can be liberated from building and maintaining the private storage infrastructure, and they can enjoy the data storage service at anywhere and anytime with high reliability and a relatively low cost. However, the security and privacy risks, especially the confidentiality and integrity of data seem to be the biggest hurdle to the adoption of the cloud storage applications. In this paper, we consider the secure data access and sharing issues for cloud storage services. Based on the intractability of the discrete logarithm problem, we design a secure data access and data sharing scheme for cloud storage, where we utilize the user authentication scheme to deal with the data access problem. According to our analysis, through our scheme, only valid user with the correct password and biometric can access to the cloud storage provider. Besides, the authorized users can access the rightful resources and verify the validity of the shared data, but cannot transfer the permission to any other party. At the same time, the confidentiality and integrity of data can be guaranteed.

     

Design of a Guitar Shaped UWB Antenna with Wide Band Notched Characteristics for Wireless Applications

Cloud storage is a cloud based service which delivers scalable on demand on line storage of data and eliminates the need of maintaining local data centre. Storage of data in cloud brings many advantages such as lower-cost, metered service, scalable and ubiquitous access. However, it also raises concerns to its integrity; to save the storage space cloud service provider may delete some rarely access data. Data privacy is another issue which must be addressed to increase data owner’s trust. To address above issues, many researchers have proposed public auditing schemes to validate the integrity of data using third party auditor. These schemes generate metadata using data files on the owner side and store these metadata on the cloud storage along with the file data, which helps in auditing. These schemes address many concerns which arise due to remote data storage. However, computation cost involved for metadata generation at the data owner side is not properly addressed; another issue which is not properly addressed is an iniquitous third party auditor may be the source of denial of service attack by issuing constantly large number of audit request. Our scheme solves these issues by lowering the computation cost at data owner side and controlling the number of times a third party auditor can issue an audit request to the cloud storage. Our Scheme also supports secure access of data using conditional proxy re-encryption scheme and delegation of auditing task by the authorized third party auditor to another auditor for the specified period of times in the case of unavailability of authorized third party auditor.

     

ACDAS: Authenticated controlled data access and sharing scheme for cloud storage

Cloud storage services require cost‐effective, scalable, and self‐managed secure data management functionality. Public cloud storage always enforces users to adopt the restricted generic security consideration provided by the cloud service provider. On the contrary, private cloud storage gives users the opportunity to configure a self‐managed and controlled authenticated data security model to control the accessing and sharing of data in a private cloud. However, this introduces several new challenges to data security. One critical issue is how to enable a secure, authenticated data storage model for data access with controlled data accessibility. In this paper, we propose an authenticated controlled data access and sharing scheme called ACDAS to address this issue. In our proposed scheme, we employ a biometric‐based authentication model for secure access to data storage and sharing. To provide flexible data sharing under the control of a data owner, we propose a variant of a proxy reencryption scheme where the cloud server uses a proxy reencryption key and the data owner generates a credential token during decryption to control the accessibility of the users. The security analysis shows that our proposed scheme is resistant to various attacks, including a stolen verifier attack, a replay attack, a password guessing attack, and a stolen mobile device attack. Further, our proposed scheme satisfies the considered security requirements of a data storage and sharing system. The experimental results demonstrate that ACDAS can achieve the security goals together with the practical efficiency of storage, computation, and communication compared with other related schemes.     

Privacy-Preserving Public Auditing for Non-manager Group Shared Data

By the widespread use of cloud storage service, users get a lot of conveniences such as low-price file remote storage and flexible file sharing. The research points in cloud computing include the verification of data integrity, the protection of data privacy and flexible data access. The integrity of data is ensured by a challenge-and-response protocol based on the signatures generated by group users. Many existing schemes use group signatures to make sure that the data stored in cloud is intact for the purpose of privacy and anonymity. However, group signatures do not consider user equality and the problem of frameability caused by group managers. Therefore, we propose a data sharing scheme PSFS to support user equality and traceability meanwhile based on our previous work HA-DGSP. PSFS has some secure properties such as correctness, traceability, homomorphic authentication and practical data sharing. The practical data sharing ensures that the data owner won’t loss the control of the file data during the sharing and the data owner will get effective incentive of data sharing. The effective incentive is realized by the technology of blockchain. The experimental results show that the communication overhead and computational overhead of PSFS is acceptable.