Biblio

Verifiable Dynamic Searchable Symmetric Encryption (VDSSE) enables users to securely outsource databases (document sets) to cloud servers and perform searches and updates. The verifiability property prevents users from accepting incorrect search results returned by a malicious server. However, we discover that the community currently only focuses on preventing malicious behavior from the server but ignores incorrect updates from the client, which are very likely to happen since there is no record on the client to check. Indeed most existing VDSSE schemes are not sufficient to tolerate incorrect updates from the client. For instance, deleting a nonexistent keyword-identifier pair can break their correctness and soundness. In this paper, we demonstrate the vulnerabilities of a type of existing VDSSE schemes that fail them to ensure correctness and soundness properties on incorrect updates. We propose an efficient fault-tolerant solution that can consider any DSSE scheme as a black-box and make them into a fault-tolerant VDSSE in the malicious model. Forward privacy is an important property of DSSE that prevents the server from linking an update operation to previous search queries. Our approach can also make any forward secure DSSE scheme into a fault-tolerant VDSSE without breaking the forward security guarantee. In this work, we take FAST [1] (TDSC 2020), a forward secure DSSE, as an example, implement a prototype of our solution, and evaluate its performance. Even when compared with the previous fastest forward private construction that does not support fault tolerance, the experiments show that our construction saves 9× client storage and has better search and update efficiency.

Now a day's cloud computing is power station to run multiple businesses. It is cumulating more and more users every day. Database-as-a-service is service model provided by cloud computing to store, manage and process data on a cloud platform. Database-as-a-service has key characteristics such as availability, scalability, elasticity. A customer does not have to worry about database installation and management. As a replacement, the cloud database service provider takes responsibility for installing and maintaining the database. The real problem occurs when it comes to storing confidential or private information in the cloud database, we cannot rely on the cloud data vendor. A curious cloud database vendor may capture and leak the secret information. For that purpose, Protected Database-as-a-service is a novel solution to this problem that provides provable and pragmatic privacy in the face of a compromised cloud database service provider. Protected Database-as-a-service defines various encryption schemes to choose encryption algorithm and encryption key to encrypt and decrypt data. It also provides "Master key" to users, so that a metadata storage table can be decrypted only by using the master key of the users. As a result, a cloud service vendor never gets access to decrypted data, and even if all servers are jeopardized, in such inauspicious circumstances a cloud service vendor will not be able to decrypt the data. Proposed Protected Database-as-a-service system allows multiple geographically distributed clients to execute concurrent and independent operation on encrypted data and also conserve data confidentiality and consistency at cloud level, to eradicate any intermediate server between the client and the cloud database.