Advanced Searchable Encryption: An Adaptively Secure Keyword Search for Matrix-type Storages

IoT technologies and cloud storages have been developed remarkably, and many types of data including private information have been gradually outsourced. For such a situation, new convenient functionalities such as arithmetic and a keyword search over ciphertexts are required to allow users to obtain information without leaking queried results, contents of ciphertext, and so on. Especially, searchable encryptions have been paid much attention to realize a keyword search on an encrypted domain. In addition, an architecture of searchable symmetric encryption (SSE) is a suitable and efficient solution for data outsourcing. In this paper, we focus on an SSE scheme which employs a secure index for searching a keyword. In conventional studies, it has been widely considered that the scheme searches whether a queried keyword is contained in encrypted documents or not. On the other hand, we additionally take into account the location of the queried keyword in the documents by targeting a matrix-type data format. The method enables an administrator to search personal information listed per line or column in CSV-like format data.