Abstract
Searchable Encryption (SE) makes it possible for users to outsource an encrypted database and search operations to cloud service providers without leaking the content of data or queries to them. A number of SE schemes have been proposed in the literature; however, most of them leak a significant amount of information that could lead to inference attacks. To minimise information leakage, there are a number of solutions, such as Oblivious Random Access Memory (ORAM) and Private Information Retrieval (PIR). Unfortunately, existing solutions are prohibitively costly and impractical. A practical scheme should support not only a lightweight user client but also a flexible key management mechanism for multi-user access.
In this position paper, we briefly analyse several leakage-based attacks, and identify a set of requirements for a searchable encryption system for cloud database storage to be secure against these attacks while ensuring usability of the system. We also discuss several possible solutions to fulfil the identified requirements.