Browsing by Author "Siva Kumar, D.V.N."

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Approaches and challenges of privacy preserving search over encrypted data
(Elsevier Ltd, 2019) Siva Kumar, D.V.N.; Santhi Thilagam, P.
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. © 2018 Elsevier Ltd
Preserving Privacy of Co-occurring Keywords over Encrypted Data
(Springer Science and Business Media Deutschland GmbH, 2021) Siva Kumar, D.V.N.; Santhi Thilagam, P.
The indexes of ranked searchable encryption contain encrypted keywords and their encrypted relevance scores. The encryption scheme of relevance scores must preserve the plaintext order after encryption so as to enable the cloud server to determine ranks of the documents directly from the encrypted keywordsâ€™ scores for a given trapdoor. Existing schemes such as Order Preserving Encryption (OPE) and One-to-Many OPE preserve the plaintext order. However, they leak the distribution information, i.e., the frequency of ciphertext values, due to the insufficient randomness employed in these schemes. The cloud server uses frequency analysis attack to infer plaintext keywords of the indexes based on the frequency leakage. In this paper, an Enhanced One-to-Many OPE scheme is proposed to minimize the frequency leakage. The proposed scheme reduces not only the frequency leakage of individual keywords but also the co-occurring keywords of the phrases like â€œcomputer networkâ€ , and â€œcommunication networkâ€ . Â© 2021, IFIP International Federation for Information Processing.
Privacy-preserving searchable encryption scheme over encrypted data supporting dynamic update
(Springer Verlag service@springer.de, 2019) Rashmi, R.; Siva Kumar, D.V.N.; Santhi Thilagam, P.S.
With the advancement of network technology, cloud computing services have become popular due to the on-demand availability of computing resources, large-scale data storage and distribution. Many users are influenced to outsource their private data to cloud servers to cut the costs of building by storing their data locally. Security and privacy protection of such outsourced data become a major security concern. To address this, the outsourced data is encrypted before it is stored on the cloud server. At the same time, users must be enabled to retrieve the data of their interest rather than going through all documents and picking up the ones that are required. This creates a need to search the encrypted data without allowing the cloud service providers know about the search query but still provide the clients with relevant documents. With data continuously changing over time, clients wish to keep their documents updated so as to maintain data consistency and enable other users to fetch the latest relevant data. However, while adding new keywords to documents, the potential positions of newly added keywords are leaked in the existing approaches. In this paper, an efficient and secure approach is proposed that returns the latest relevant documents and also preserves the privacy of updated keywords. Â© Springer Nature Singapore Pte Ltd. 2019.
Searchable encryption approaches: attacks and challenges
(2019) Siva Kumar, D.V.N.; Santhi Thilagam, P.
Searchable encryption (SE) is a cryptographic technique that allows the users to perform search over outsourced encrypted data in cloud servers while preserving the privacy of data and search query. In order to preserve privacy and security, data owners use various encryption schemes to encrypt their data and indexes. Due to the vulnerabilities in the encryption schemes adopted by SE schemes, information leakages are possible from the encrypted data. The cloud servers use various information disclosure attacks that exploit these leakages to infer plaintext information. In this paper, we analyze the existing SE approaches with respect to their security and precision goals and possible attacks on them. We also identify the root causes of these attacks and their remedies. An experimental study is also performed to investigate the susceptibility of SE schemes against attacks and countermeasures to prevent them. 2018, Springer-Verlag London Ltd., part of Springer Nature.
Searchable encryption approaches: attacks and challenges
(Springer London, 2019) Siva Kumar, D.V.N.; Santhi Thilagam, P.
Searchable encryption (SE) is a cryptographic technique that allows the users to perform search over outsourced encrypted data in cloud servers while preserving the privacy of data and search query. In order to preserve privacy and security, data owners use various encryption schemes to encrypt their data and indexes. Due to the vulnerabilities in the encryption schemes adopted by SE schemes, information leakages are possible from the encrypted data. The cloud servers use various information disclosure attacks that exploit these leakages to infer plaintext information. In this paper, we analyze the existing SE approaches with respect to their security and precision goals and possible attacks on them. We also identify the root causes of these attacks and their remedies. An experimental study is also performed to investigate the susceptibility of SE schemes against attacks and countermeasures to prevent them. © 2018, Springer-Verlag London Ltd., part of Springer Nature.