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。     

利用可信计算技术改善云计算的安全性

云计算影响了互联网上世界上任何地方远程服务器处理、数据存储和共享的方式。这种共享多种分布式资源方式,使得安全问题更加复杂化。本文分析了云计算环境下的安全服务,通过整合可信计算环境来建立云计算系统。可信计算平台模式可以提高云计算的安全性。可信计算模式重要的安全服务包括加密,认证,完整性和保密性等都可以用在云计算系统中。     

Towards Developing Privacy-Preserved Data Security Approach (PP-DSA) in Cloud Computing Environment

In the present scenario of rapid growth in cloud computing models, several companies and users started to share their data on cloud servers. However, when the model is not completely trusted, the data owners face several security-related problems, such as user privacy breaches, data disclosure, data corruption, and so on, during the process of data outsourcing. For addressing and handling the security-related issues on Cloud, several models were proposed. With that concern, this paper develops a Privacy-Preserved Data Security Approach (PP-DSA) to provide the data security and data integrity for the outsourcing data in Cloud Environment. Privacy preservation is ensured in this work with the Efficient Authentication Technique (EAT) using the Group Signature method that is applied with Third-Party Auditor (TPA). The role of the auditor is to secure the data and guarantee shared data integrity. Additionally, the Cloud Service Provider (CSP) and Data User (DU) can also be the attackers that are to be handled with the EAT. Here, the major objective of the work is to enhance cloud security and thereby, increase Quality of Service (QoS). The results are evaluated based on the model effectiveness, security, and reliability and show that the proposed model provides better results than existing works.     

基于同态hash的数据多副本持有性证明方案

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,在分析并指出一个基于同态hash的数据持有性证明方案安全缺陷的基础上,对其进行了改进和扩展,提出了一个多副本持有性证明方案。为实现多副本检查,将各副本编号与文件连接后利用相同密钥加密以生成副本文件,既有效防止了CSP各服务器的合谋攻击,又简化了用户和文件的授权访问者的密钥管理;为提高检查效率,利用同态hash为数据块生成验证标签,实现了对所有副本的批量检查;为保证方案安全性,将文件标志和块位置信息添加到数据块标签中,有效防止了CSP进行替换和重放攻击。安全性证明和性能分析表明,该方案是正确和完备的,并具有计算、存储和通信负载低,以及支持公开验证等特点,从而为云存储中数据完整性检查提供了一种可行的方法。     

基于多云服务器的企业网盘设计与实现

针对现有企业网盘存在的安全隐患、传输性能较差、可靠性不高、运营商锁定等问题。该文 从网盘存储的机密性、可靠性和访问效率等方面,设计和实现一种基于多云服务器的安全企业网盘系 统——SkyDisk,实现了数据的自主可控、高速存取和安全可靠。其中,基于 Tahoe-LAFS 系统将多个 云服务器整合成分布式存储集群,为网盘系统提供后端存储服务;文件在存储之前采用 256 位高级加 密标准加密,保证数据的机密性;通过纠删编码和分散存储保证数据的可靠性;本地网盘服务器与多 个云服务器之间并行传输数据,实现了高速上传和下载。最终,SkyDisk 实现一个 Web 服务,向用户 提供 Web 方式的网盘系统。系统测试结果表明,SkyDisk 能够实现安全、可靠的文件存储管理,多云 服务器存储集群没有单节点故障。同时,能够满足快速上传、下载和便捷的文件分享等功能性需求, 降低了企业文件管理成本、提高了生产效率和企业竞争力。     

A highly secured and streamlined cloud collaborative editing scheme along with an efficient user revocation in cloud computing

These days with the expanded fame of cloud computing, the interest for cloud-based collaborative editing service is rising. The encryption method is utilized to ensure and secure the data, during the collaborative editing process. In the encryption process, the cloud requires more time to work the collaborative editing. This paper proposes an efficient scheme for reducing the encryption burden over the cooperative users, as the possibilities of cooperative users read and write data by means of any gadget. In the proposed scheme, the encrypted file sent by the data owner is split into smaller segments and stored in the cloud by the cloud service provider (CSP) along with specific tags. Once the cooperative user receives and decrypts the file from the CSP, it modifies and encrypts only the modified segment and resends to the CSP. The CSP after verifying the signature replace the original file segment in the cloud with the modified segment based on the tag information. The scheme that is put forward is performed based on the modified ciphertext-policy hierarchical attribute–based encryption, and the security process is done based on the attribute-based signature schemes. This work employs a proficient attribute updating method to accomplish the dynamic change of users' attributes, consisting granting new attributes, revoking previous attributes, and regranting formerly revoked attributes. A writer's attributes and keys have been revoked, and the stale information cannot be written.     

基于云存储的多用户可搜索加密方案

云存储服务允许用户外包数据并以此来降低资源开销。针对云服务器不被完全信任的现状,文章研究如何在云环境下对数据进行安全存储和加密搜索。多用户的可搜索加密方案为用户提供了一种保密机制,使用户可以在不受信任的云存储环境下安全地共享信息。在现有的可搜索加密方案的基础上,文章提出了一种安全有效的带关键字搜索的加密方案,以及更加灵活的密钥管理机制,降低了云端数据处理的开销。     

Data storage auditing service in cloud computing: challenges,methods and opportunities

Cloud computing is a promising computing model that enables convenient and on-demand network access to a shared pool of configurable computing resources. The first offered cloud service is moving data into the cloud: data owners let cloud service providers host their data on cloud servers and data consumers can access the data from the cloud servers. This new paradigm of data storage service also introduces new security challenges, because data owners and data servers have different identities and different business interests. Therefore, an independent auditing service is required to make sure that the data is correctly hosted in the Cloud. In this paper, we investigate this kind of problem and give an extensive survey of storage auditing methods in the literature. First, we give a set of requirements of the auditing protocol for data storage in cloud computing. Then, we introduce some existing auditing schemes and analyze them in terms of security and performance. Finally, some challenging issues are introduced in the design of efficient auditing protocol for data storage in cloud computing.     

IaaS环境可信证明方法研究

提出一种基于时间戳的基础设施即服务(IaaS)动态可信证明方法。通过对云节点进行实时的动态度量,并将度量结果与度量时间绑定,验证云节点的当前运行状态可信。基于该方法,结合IaaS的服务业务流程,设计云节点注册证明、虚拟机启动证明及虚拟机关闭证明等远程证明方法,证明用户虚拟机运行于状态可信的云节点上,同时保证虚拟机数据的完整性和机密性。     

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.     

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。     

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.     

Multi-Authority-Based File Hierarchy Hidden CP-ABE Scheme for Cloud Security

Cloud technology is emerging as a widely accepted technology in the recent years due to its robust nature. Cloud computation is basically developed on the fact that the resources can be shared between numerous devices to achieve efficient network operation among devices with minimized computation expenses. However, the sharing nature poses a security risk for the devices whose resources are being shared. Almost in all the existing works on cloud security, a single trusted third party (TTP) is used for key issue and authorization. However, using a single TTP may results in single-point failure and security risks. Most of the previous works on cloud security focus on storage security rather than considering the computation security. In order to solve these issues, in this paper, multi-authority-based file hierarchy hidden CP-ABE scheme for cloud security is proposed. In this scheme, the files are arranged in hierarchical order based on their attribute weights. Then when a cloud user needs certain resources, it requests the cloud service provider (CSP). The CSP links with the cloud owner to provide the requested file after encrypting it. The cloud server encrypts and places the encrypted file in CSP, which is later retrieved by cloud user. In this way, all the files that are being used are encrypted along with strict authentication to ensure cloud security.     

Engineering of secure multi-cloud storage

This article addresses security and privacy issues associated with storing data in public cloud services. It presents an architecture based on a novel secure cloud gateway that allows client systems to store sensitive data in a semi-trusted multi-cloud environment while providing confidentiality, integrity, and availability of data. This proxy system implements a space-efficient, computationally-secure threshold secret sharing scheme to store shares of a secret in several distinct cloud datastores. Moreover, the system integrates a comprehensive set of security measures and cryptographic protocols to mitigate threats induced by cloud computing. Performance in practice and code quality of the implementation are analyzed in extensive experiments and measurements.     

云计算中密码应用模式初探

文章在分析云计算安全风险的基础上,阐述了云计算中的密码应用模式,包括密码应用模式框架和云计算中用户数据的加密方式,重点针对云计算中动态数据的机密性,从可信计算平台、安全虚拟机、密码协处理器和虚拟桌面技术等四方面,讨论了密码应用的新模式。     

支持错误定位的远程数据完整性批量验证方案

远程数据完整性验证技术是保证云数据安全的一种重要技术,能通过与服务器进行少量交互,验证外包数据是否完整。在现实中,云存储服务通常是在多用户与多服务器之间存在的,最近多用户与多服务器环境下的批处理验证方案陆续被提出。但这些方案在数据出错后,往往于一次挑战中无法判定错误数据的拥有者或所在服务器。利用Merkle Hash Tree（MHT）提出了一种支持错误数据定位的批处理校验方案,可以在批处理校验不通过后,同时定位出错误数据的拥有者与其所存储的服务器。     

基于区块链与可信计算的数据交易方案

针对当前数据交易过程中数据容易被拷贝的问题以及数据保密的实现,提出一种基于区块链与可信计算的数据交易方案。首先,利用区块链记录数据信息、交易信息以及数据使用记录,这可帮助数据资产确权以及数据溯源;然后,利用可信计算与加密算法来保证交易数据传输安全;最后,用数据主体与数据需求方提供的算法在可信计算环境中完成计算,之后输出结果并加密返回给需求方。所提方案在确保数据主体不泄露数据的情况下,让需求方可以使用数据进行计算,且通过可信加密保证了传输安全。     

电子文件归档的安全性分析

针对电子文件移交归档的安全应用需求,提出一种基于密码技术、可信网络、电子印章、数字水印、版权保护等技术的电子文件归档与利用的安全方案,并分析了该安全方案的应用模型.应用数字版权保护、版式文件、全程加密、打印控制和电子印章与数字水印等技术,解决了电子文件归档与利用中的惟一性、真实性、完整性、安全性、防扩散和防复制等问题.     

Towards Public Integrity Audition for Cloud-IoT Data Based on Blockchain

With the rapidly developing of Internet of Things (IoT), the volume of data generated by IoT systems is increasing quickly. To release the pressure of data management and storage, more and more enterprises and individuals prefer to integrate cloud service with IoT systems, in which the IoT data can be outsourced to cloud server. Since cloud service provider (CSP) is not fully trusted, a variety of methods have been proposed to deal with the problem of data integrity checking. In traditional data integrity audition schemes, the task of data auditing is usually performed by Third Party Auditor (TPA) which is assumed to be trustful. However, in real-life TPA is not trusted as people thought. Therefore, these schemes suffer from the underlying problem of single-point failure. Moreover, most of the traditional schemes are designed by RSA or bilinear map techniques which consume heavy computation and communication cost. To overcome these shortcomings, we propose a novel data integrity checking scheme for cloud-IoT data based on blockchain technique and homomorphic hash. In our scheme, the tags of all data blocks are computed by a homomorphic hash function and stored in blockchain. Moreover, each step within the process of data integrity checking is signed by the performer, and the signatures are stored in blockchain through smart contracts. As a result, each behavior for data integrity checking in our scheme can be traced and audited which improves the security of the scheme greatly. Furthermore, batch-audition for multiple data challenges is also supported in our scheme. We formalize the system model of our scheme and give the concrete construction. Detailed performance analyses demonstrate that our proposed scheme is efficient and practical without the trust-assumption of TPA.     

一种基于区块链的安全云存储方案设计

云存储方式是将数据上传到云服务器中,以此来减轻本地存储的负担。然而,把数据存储到不受信任的第三方云服务器上,可能导致一些数据安全隐患的出现,其中最典型的是数据的完整性问题和隐私问题。针对数据完整性问题和隐私问题,提出一种基于区块链的云存储方案。该方案利用区块链的梅克尔树属性、匿名性、不可篡改等特点构建安全云存储系统,有效地解决了数据完整性问题和隐私保护问题。