## Cryptology ePrint Archive: Report 2016/981

Efficient No-dictionary Verifiable SSE

Wakaha Ogata and Kaoru Kurosawa

Abstract: In the model of "no-dictionary" verifiable searchable symmetric encryption (SSE) scheme, a client does not need to keep the set of keywords ${\cal W}$ in the search phase, where ${\cal W}$ is called a dictionary. Still a malicious server cannot cheat the client by saying that your search word $w$ does not exist in the dictionary ${\cal W}$" when it exists. In the previous such schemes, it takes $O(\log m)$ time for the server to prove that $w \not\in {\cal W}$, where $m=|{\cal W}|$ is the number of keywords. In this paper, we show a generic method to transform any SSE scheme (that is only secure against passive adversaries) to a no-dictionary verifiable SSE scheme. In the transformed scheme, it takes only $O(1)$ time for the server to prove that $w \not\in {\cal W}$.

Category / Keywords: cryptographic protocols / searchable symmetric encryption, verifiable, dictionary