Public key encryption with distributed keyword search

Abstract

In cloud storage, data owners usually achieve confidentiality of information through giving encrypted data to the server and as a consequence, the possibility of searching over the database is lost. Searchable encryption (SE) is a method to encrypt data in such a way that keyword searching would still be possible. However, to the best of our knowledge, existing literature on SE schemes only supports search operations carried out by an individual users. In this paper, we introduce the concept of public key encryption with distributed keyword search (PEDKS) to provide a solution for scenarios where the search ability can be distributed among authorized subsets of users according to a predefined access structure. Therefore, by employing a PEDKS, group members realizing the specified access structure can cooperatively query to search. We further propose a concrete construction of a PEDKS scheme and prove its security under the intractability of ECDL and BDH problems. Performance analysis and comparison with related concepts are provided as well.

Subject Classification:

• 94A60
• 68P25
• 94A62
• 68P20
• 68P10

Keywords:

• Searchable encryption
• Public key encryption
• Distributed keyword search
• Secret sharing
• Access structure