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。     

Lightweight integrity verification scheme for cloud based group data

In order to protect the security of the data stored in the cloud by group users,a data integrity verification scheme was designed which can protect the privacy of the group users.The scheme can efficiently detect the shared data in the cloud and support the dynamic updating of the data,and use the characteristic of the ring signature to hide the iden-tity of the signer corresponding to the data block.That is,the third-party verifier can not spy on the users identity and other private information when validating.The aggregated approach is used to generate data labels,which reduces the storage cost of labels and supports the dynamic operation of group data,so that the users in the group can easily modify the cloud group data.     

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.     

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.     

Public integrity verification for data sharing in cloud with asynchronous revocation

Cloud data sharing service, which allows a group of people to access and modify the shared data, is one of the most popular and efficient working styles in enterprises. Recently, there is an uprising trend that enterprises tend to move their IT service from local to cloud to ease the management and reduce the cost. Under the new cloud environment, the cloud users require the data integrity verification to inspect the data service at the cloud side. Several recent studies have focused on this application scenario. In these studies, each user within a group is required to sign a data block created or modified by him. While a user is revoked, all the data previously signed by him should be resigned. In the existing research, the resigning process is dependent on the revoked user. However, cloud users are autonomous. They may exit the system at any time without notifying the system admin and even are revoked due to misbehaviors. As the developers in the cloud-based software development platform, they are voluntary and not strictly controlled by the system. Due to this feature, cloud users may not always follow the cloud service protocol. They may not participate in generating the resigning key and may even expose their secret keys after being revoked. If the signature is not resigned in time, the subsequent verification will be affected. And if the secret key is exposed, the shared data will be maliciously modified by the attacker who grasps the key. Therefore, forcing a revoked user to participate in the revocation process will lead to efficiency and security problems. As a result, designing a practical and efficient integrity verification scheme that supports this scenario is highly desirable. In this paper, we identify this challenging problem as the asynchronous revocation, in which the revocation operations (i.e., re-signing key generation and resigning process) and the user's revocation are asynchronous. All the revocation operations must be able to be performed without the participation of the revoked user. Even more ambitiously, the revocation process should not rely on any special entity, such as the data owner or a trusted agency. To address this problem, we propose a novel public data integrity verification mechanism in which the data blocks signed by the revoked user will be resigned by another valid user. From the perspectives of security and practicality, the revoked user does not participate in the resigning process and the re-signing key generation. Our scheme allows anyone in the cloud computing system to act as the verifier to publicly and efficiently verify the integrity of the shared data using Homomorphic Verifiable Tags (HVTs). Moreover, the proposed scheme resists the collusion attack between the cloud server and the malicious revoked users. The numerical analysis and experimental results further validate the high efficiency and scalability of the proposed scheme. The experimental results manifest that re-signing 10,000 data blocks only takes 3.815 ?s and a user can finish the verification in 300 ?ms with a 99% error detection probability.     

云计算中数据隐私保护研究进展

由于社会分工和资源共享的必然,公共云平台必将成为和电网、互联网等同等重要的国家基础设施。云计算面临的安全问题制约着云计算的广泛使用。数据安全在云计算中尤为重要,如何保证数据的安全性是云计算安全的核心。从数据的隐私保护计算、数据处理结果的完整性认证、数据访问权限控制以及数据的物理安全4个方面对已有研究工作进行了分类和总结,为后续云计算中数据的安全性研究提供参照。     

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.     

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.     

云计算与区块链平台的遥感影像安全检索方案

遥感影像外包到半可信的云平台进行存储和检索时,可能导致影像数据的泄露和返回不完整的检索结果。加密可以保护影像数据的安全,但无法保证云平台提供真实、完整的存储和检索服务。区块链技术能有效保证存储和检索服务的真实性和完整性,但区块链的计算和存储能力有限,如何实现遥感影像的安全存储和检索仍是一个具有挑战性的问题。该文提出一种结合云平台和区块链的遥感影像安全检索方法,将影像哈希等轻量级数据存储于区块链,云平台存储海量加密影像数据,确保云存储影像的真实性;区块链执行基于遥感影像属性的检索,在此基础上由云平台执行复杂度较高的基于内容的安全检索,保证了检索结果的完整性;利用区块链技术设计遥感影像检索交易机制。实验表明方案可以实现安全、真实、完整和高效的遥感影像检索,并构建一个双方信任的公平交易环境。     

云计算中的轻量级查询结果验证机制

存储在云计算服务器上的数据可能被篡改或删除,查询完整性验证的作用是确保查询用户能够验证查询结果中的数据是真实的,且包含所有满足条件的数据。提出了一种基于签名链结构的查询完整性验证机制。方案使用代数签名机制替代数字签名实现校验值的计算,从而有效降低计算和查询验证开销。此外,通过维护一种新的、简单的索引结构实现了仅需下载少量数据即可实现校验值的更新。实验结果表明,所提方案比基于数字签名的签名链方案具有更小的更新开销和更高的验证效率。     

基于UVM的AXI总线验证IP设计

基于UVM技术设计了可用于验证AXI总线协议的验证IP,对支持AXI4接口的Block RAM IP进行了验证,并构建了多Master和多Slave互联模拟验证平台,验证多AXI设备互联场景。设计了三种类型的测试用例(随机测试、基础测试和错误测试),并通过统计功能覆盖率来评估验证的完整性。验证结果表明,该验证IP功能正确,可满足对AXI总线的验证要求,功能覆盖率达到100%。     

基于行为的云计算访问控制安全模型

针对当前流行的云计算技术,分析了其所面临的安全问题。以BLP(Bell-LaPadula)模型和Biba模型为参考,通过基于行为的访问控制技术来动态调节主体的访问范围,实现BLP模型和Biba模型的有机结合,提出了CCACSM(cloud computing access control security model)。该模型不仅能保护云端服务器中数据完整性和保密性,而且使云计算环境具有相当的灵活性和实用性。最后给出了该模型的组成部分、安全公理和实现过程。     

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.     

QMLFD Based RSA Cryptosystem for Enhancing Data Security in Public Cloud Storage System

Nowadays sharing secure data turns out to be a challenging task for the data owner due to its privacy and confidentiality. Several IT companies stores their important information in the cloud since computing has developed immense power in sharing the data. On the other hand, privacy is considered a serious issue in cloud computing as there are numerous privacy concerns namely integrity, authentication as well as confidentiality. Among all those concerns, this paper focuses on enhancing the data integrity in the public cloud environment using Qusai modified levy flight distribution for the RSA cryptosystem (QMLFD-RSA). An effective approach named QMLFD for the RSA cryptosystem is proposed for resolving the problem based on data integrity in public cloud environment. A secured key generation and data encryption are done by employing the RSA cryptosystem thus the data is secured from unauthorized users. The key selection is done by using quasi based modified Levy flight distribution algorithm. Thus the proposed approach provides an effective model to enhance the integrity of data in cloud computing thus checking the data integrity uploaded in the public cloud storage system. In addition to this, ten optimization benchmark functions are calculated to determine the performances and the functioning of the newly developed QMLFD algorithm. The simulation results and comparative performances are carried out and the analysis reveals that the proposed QMLFD for the RSA cryptosystem provides better results when compared with other approaches.

     

基于多分支认证树的多用户多副本数据持有性证明方案

在云存储环境下,如何高效、动态地完成对多用户多副本数据的完整性验证是一个挑战性问题。基于双线性代数映射的签名机制和多分支认证树特性,提出了一种新的多用户多副本数据持有性证明方案。该方案通过使用随机掩码技术对密文进行处理确保数据隐私性,采用多分支认证树来提高数据分块的签名效率,能够支持数据动态更新操作。此外,引入第三方审计者对多用户多副本数据进行批量审计以减少计算开销。最后,分析表明本方案具有较高的安全性和效率。     

一种适用于工业控制系统的加密传输方案

随着工业物联网(IoT)、云计算等信息技术与工业控制系统(ICS)的整合,工业数据的安全正面临着极大风险。为了能在这样一个复杂的分布式环境中保护数据的机密性和完整性,该文采用基于属性的加密(ABE)算法,设计一种集数据加密、访问控制、解密外包、数据验证为一体的通信方案,同时具有密文长度恒定的特点。最后,从正确性、安全性和性能开销3个方面对方案进行详细的分析,并通过仿真验证得出该算法具有低解密开销的优势。     

一种基于ORAM的数据可恢复性证明与访问模式的隐藏

随着云计算的发展与应用,越来越多的客户选择云存储作为存储媒质,因此,数据的完整性和私密性成为客户关心的主要问题。基于无关RAM模型机提出一种新的结构,将客户文件分割成大小相等的数据块,每个数据块在云存储中有两个备份,且随机地存储在不同的文件中,以保证数据的完整性。利用同态散列算法验证数据的可持有性,通过无关RAM隐藏客户对服务器的访问模式,敌手无法从客户的数据访问模式中获取有用的信息,从而实现了数据的私密性。     

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.     

Identity-based cloud storage integrity checking from lattices

With the rapid development of cloud storage,more and more users are storing their data in the cloud.To verify whether the users’ data stored in the cloud is corrupted,one effective method is to adopt cloud storage integrity checking schemes.An identity-based cloud storage integrity checking scheme was proposed on the small integer solution problem over ideal lattices,and it was proven to be secure against the adaptive identity attacks of clouds in the random oracle model.To validate the efficiency of the scheme,extensive experiments were conducted to make performance-comparisons between the scheme and the existing two identity-based cloud storage integrity checking schemes.The experimental results show that the online tag-generation time and the proof-verification time of the scheme are respectively reduced by 88.32%～93.74% and 98.81%～99.73%.     

光纤网络中云计算资源联合最优分配方法

在云计算技术与光纤网络不断发展的今天,网络数据不断增加,网络带宽面临严峻挑战。当前应用云计算资源联合最优分配方法对网络链路资源分配的结果较为落后,导致资源分配后网络数据传输扰动量以及带宽阻塞率较高。针对此问题,本文设计光纤网络中云计算资源联合最优分配方法。以网络任务模型为蓝本,构建光纤网络传输模型。将光纤网络传输模型以有向图的形式,完成网络节点传输映射分析。结合光树生成算法,设计云计算资源最优分配算法,完成光纤网络中云计算资源联合最优分配方法设计。仿真结果表明：采用所提方法后网络数据传输扰动量以及带宽阻塞率较低,提升了云计算资源的分配方法。