云存储中加密数据的相似检索技术应用研究

随着云存储的广泛应用，大量数据存储在云服务器。尽管云服务提供很多便利，但数据的隐私及安全性一直是重点关注的问题，为解决数据安全问题需要将外储数据以加密的形式进行存储。加密存储的方式保护了数据不被恶意访问，然而数据的一些重要的基本应用如检索等不能实现。为了在不泄露隐私的条件下实现对加密数据的检索，很多可检索的加密方案被提出。然而，这些方案多数只能处理确切的关键字匹配检索而不能进行相似的关键字检索，相似检索在现实应用中又极其重要。本文提出一个高效的支持加密数据相似检索的方案，为了实现相似密文的检索我们利用一种被称为位置敏感的哈希算法。为了确保数据的机密性和安全性，我们给出了严格的安全定义，并且在安全定义下证明了方案的安全性。      

云计算环境下支持排名的关键词加密检索方法

随着云计算的出现,越来越多的数据开始集中存储到云端,为了保护数据隐私,敏感数据需要在外包到云端之前进行加密,使在加密数据上进行有效检索成为一个挑战性任务。尽管传统的加密检索模型支持在加密数据上进行关键词检索,但是它们没有描述检索结果的相关度,导致返回所有包含关键词的检索结果占用了大量的网络带宽,并且用户从返回的检索结果中再次选择最相关的结果也会产生大量的时间开销,为此,提出了云计算环境下支持排名的关键词加密检索方法。该方法根据相关度返回排序后的检索结果,其中的保序对称加密模型不仅防止了相关度信息的泄漏,而且提供了高效的检索性能。实验表明了该方法的有效性。     

Multiuser access control searchable privacy‐preserving scheme in cloud storage

Searchable encryption scheme‐based ciphertext‐policy attribute‐based encryption (CP‐ABE) is a effective scheme for providing multiuser to search over the encrypted data on cloud storage environment. However, most of the existing search schemes lack the privacy protection of the data owner and have higher computation time cost. In this paper, we propose a multiuser access control searchable privacy‐preserving scheme in cloud storage. First, the data owner only encrypts the data file and sets the access control list of multiuser and multiattribute for search data file. And the computing operation, which generates the attribute keys of the users' access control and the keyword index, is given trusted third party to perform for reducing the computation time of the data owner. Second, using CP‐ABE scheme, trusted third party embeds the users' access control attributes into their attribute keys. Only when those embedded attributes satisfy the access control list, the ciphertext can be decrypted accordingly. Finally, when the user searches data file, the keyword trap door is no longer generated by the user, and it is handed to the proxy server to finish. Also, the ciphertext is predecrypted by the proxy sever before the user performs decryption. In this way, the flaw of the client's limited computation resource can be solved. Security analysis results show that this scheme has the data privacy, the privacy of the search process, and the collusion‐resistance attack, and experimental results demonstrate that the proposed scheme can effectively reduce the computation time of the data owner and the users.     

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.     

云环境下安全的可验证多关键词搜索加密方案

云计算的高虚拟化与高可扩展性等优势,使个人和企业愿意外包加密数据到云端服务器。然而,加密后的外包数据破坏了数据间的关联性。尽管能够利用可搜索加密(SE)进行加密数据的文件检索,但不可信云服务器可能篡改、删除外包数据或利用已有搜索陷门来获取新插入文件相关信息。此外,现有单关键词搜索由于限制条件较少,导致搜索精度差,造成带宽和计算资源的浪费。为了解决以上问题,提出一种高效的、可验证的多关键词搜索加密方案。所提方案不仅能够支持多关键词搜索,也能实现搜索模式的隐私性和文件的前向安全性。此外,还能实现外包数据的完整性验证。通过严格的安全证明,所提方案在标准模型下被证明是安全的,能够抵抗不可信云服务器的离线关键词猜测攻击(KGA)。最后,通过与最近3种方案进行效率和性能比较,实验结果表明所提方案在功能和效率方面具有较好的综合性能。     

云计算环境下密文搜索算法的研究

为确保数据私密性,用户选择将数据加密后再上传到云端,但云无法为密文数据提供管理和搜索等服务。密文搜索技术可以把保护用户数据私密性和有效利用云服务结合起来。在分析云环境下密文搜索算法的基础上,提出基于云环境的密文搜索体系结构,研究其中的关键技术,指出云环境应用密文搜索技术存在的问题和改进的方向。     

云环境下安全密文区间检索方案的新设计

针对目前密文区间检索多次断言存在信息泄露等问题,有单断言的密文区间检索方案(SRQSAE方案),并证明方案在唯密文攻击下的隐私安全性。对SRQSAE方案的安全性进行了分析,分析结果表明SRQSAE方案并不能隐藏搜索关键字的大小关系排序。通过在每次生成搜索索引或陷门消息时引入不同随机数的方法,提出了单断言的密文区间检索新方案。新方案对搜索关键字、区间的大小关系提供了很好的隐私保护;而且新方案在安全性提高的同时,并不以损失效率为代价。     

Data access control policy of encrypted deduplication system

To solve the problem that convergent encryption was commonly used in existing encrypted deduplication systems in cloud storage and data owner couldn’t effectively enforce access control on their outsourced data,an encrypted deduplication system was proposed to support access control functions such as identity authentication,authorization deduplication and the update of access control policy.The outsourced data was only deduplicated with the authorized users,and the unauthorized users couldn’t obtain any data information.CP-ABE and the partition of the ElGamal private key were used to update the access control policy of data.Self-control objects was used to encapsulate user’s data and its access policy,providing authentication for data visitors and ensuring the access control policies enforced effectively.Security analysis and simulation results demonstrate that the proposed system enables data access control and executes efficiently.     

Secure personal data sharing in cloud computing using attribute-based broadcast encryption

The ciphertext-policy (CP) attribute-based encryption (ABE) (CP-ABE) emergings as a promising technology for allowing users to conveniently access data in cloud computing. Unfortunately, it suffers from several drawbacks such as decryption overhead, user revocation and privacy preserving. The authors proposed a new efficient and privacy-preserving attribute-based broadcast encryption (BE) (ABBE) named EP-ABBE, that can reduce the decryption computation overhead by partial decryption, and protect user privacy by obfuscating access policy of ciphertext and user's attributes. Based on EP-ABBE, a secure and flexible personal data sharing scheme in cloud computing was presented, in which the data owner can enjoy the flexibly of encrypting personal data using a specified access policy together with an implicit user index set. With the proposed scheme, efficient user revocation is achieved by dropping revoked user's index from the user index set, which is with very low computation cost. Moreover, the privacy of user can well be protected in the scheme. The security and performance analysis show that the scheme is secure, efficient and privacy-preserving.     

具有隐私保护的完整性可验证的关键字搜索方案

针对传统基于属性关键字搜索(ABKS)方案存在访问结构泄密、用户侧计算量高及缺乏完整性验证问题,该文提出具有隐私保护和完整性可验证的基于属性的关键字搜索方案。该方案提出了有序多值属性访问结构和有序多值属性集,固定每个属性的位置,减少参数及相关计算,提高了方案的效率,而在密钥生成时计算具体属性取值的哈希值,从而达到区别多值属性取值的不同。同时,采用Hash和对运算实现对访问结构的隐藏,防止访问结构泄密;采用倒序索引结构和Merkle树建立数据认证树,可验证云服务器返回文档和外包解密结果的正确性。此外,支持外包解密以降低用户侧的计算量。安全分析和实验表明所提方案实现云中共享数据的可验证性、关键字不可区分性和关键字不可链接性,且是高效的。     

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。     

EEPPDA—Edge-enabled efficient privacy-preserving data aggregation in smart healthcare Internet of Things network

The Internet of Things-based smart healthcare provides numerous facilities to patients and medical professionals. Medical professionals can monitor the patient's real-time medical data and diagnose diseases through the medical health history stored in the cloud database. Any kind of attack on the cloud database will result in misdiagnosis of the patients by medical professionals. Therefore, it becomes a primary concern to secure private data. On the other hand, the conventional data aggregation method for smart healthcare acquires immense communication and computational cost. Edge-enabled smart healthcare can overcome these limitations. The paper proposes an edge-enabled efficient privacy-preserving data aggregation (EEPPDA) scheme to secure health data. In the EEPPDA scheme, captured medical data have been encrypted by the Paillier homomorphic cryptosystem. Homomorphic encryption is engaged in the assurance of secure communication. For data transmission from patients to the cloud server (CS), data aggregation is performed on the edge server (ES). Then aggregated ciphertext data are transmitted to the CS. The CS validates the data integrity and analyzes and processes the authenticated aggregated data. The authorized medical professional executes the decryption, then the aggregated ciphertext data are decrypted in plaintext. EEPPDA utilizes the batch verification process to reduce communication costs. Our proposed scheme maintains the privacy of the patient's identity and medical data, resists any internal and external attacks, and verifies the health data integrity in the CS. The proposed scheme has significantly minimized computational complexity and communication overhead concerning the existing approach through extensive simulation.     

Trapdoor Security Lattice-Based Public-Key Searchable Encryption with a Designated Cloud Server

Cloud storage technique has becoming increasingly significant in cloud service platform. Before choosing to outsource sensitive data to the cloud server, most of cloud users need to encrypt the important data ahead of time. Recently, the research on how to efficiently retrieve the encrypted data stored in the cloud server has become a hot research topic. Public-key searchable encryption, as a good candidate method, which enables a cloud server to search on a collection of encrypted data with a trapdoor from a receiver, has attracted more researchers’ attention. In this paper, we propose the frist efficient lattice-based public-key searchable encryption with a designated cloud server, which can resist quantum computers attack. In our scheme, we designate a unique cloud server to test and return the search results, thus can remove the secure channel between the cloud server and the receiver. We have proved that our scheme can achieve ciphertext indistinguishability under the hardness of learning with errors, and can achieve trapdoor security in the random oracle model. Moreover, our scheme is secure against off-line keyword guessing attacks from outside adversary.     

面向6G的雾无线接入网内生安全数据共享机制研究

为解决6G移动通信系统中雾无线接入网中数据共享的数据安全问题,提出了一种实现本地差分隐私和动态批量审计的内生安全数据共享机制.首先,用户本地对数据运行RAPPOR算法保护数据隐私;其次,雾接入点对数据进行缓存和预处理;再次,大功率节点对雾接入点上的数据进行基于BLS签名和Merkle哈希树的数据完整性审计;最后,BBU...     

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.     

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.     

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.     

A based on blinded CP‐ABE searchable encryption cloud storage service scheme

Cloud computing has great economical advantages and wide application, more and more data owners store their data in the cloud storage server (CSS) to avoid tedious local data management and insufficient storage resources. But the privacy of data owners faces enormous challenges. The most recent searchable encryption technology adopts the ciphertext‐policy attribute‐based encryption (CP‐ABE), which is one good method to deal with this security issue. However, the access attributes of the users are transmitted and assigned in plaintext form. In this paper, we propose a based on blinded CP‐ABE searchable encryption cloud storage service (BCP‐ABE‐SECSS) scheme, which can blind the access attributes of the users in order to prevent the collusion attacks of the CSS and the users. Data encryption and keyword index generation are performed by the data owners; meanwhile, we construct that CSS not only executes the access control policy of the data but also performs the pre‐decryption operation about the encrypted data to solve higher time cost of decryption calculation to the data users. Security proof results show that this scheme has access attribute security, data confidentiality, indistinguishable security against chosen keyword attack, and resisting the collusion attack between the data user and the CSS. Performance analysis and the experimental results show that this scheme can effectively reduce the computation time cost of the data owners and the data users.     

基于区块链的多关键词模糊搜索加密方案

针对1对多数据密文共享中多关键词模糊匹配和用户公平性问题,该文提出一种基于区块链的多关键词模糊搜索加密方案。该文提出一种R-HashMap索引结构,通过使用对偶编码函数和位置敏感哈希函数来构建安全索引,并采用K最近邻算法来加密索引,通过计算欧式距离度量查询关键词向量与索引节点之间的相似性,实现多关键词模糊密文搜索。该文除了消除预定义词典和降低存储开销外,还在不增加搜索复杂度的前提下实现对安全索引的更新。此外,将以太坊区块链技术与可搜索加密方案相结合避免了恶意服务器对数据的篡改,使用智能合约作为可信第三方进行检索工作,不仅可以防止云服务器内部的关键词猜测攻击,还可以解决检索结果不正确的问题。通过安全性证明分析,该文不但满足自适应选择关键词语义安全性,还可以保护用户隐私和数据安全。将该文与其他方案进行实验对比,证明该文在保证精确度的前提下,时间开销上具有更好的效率优势。     

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.