A Transformation from Attribute-based Encryption to Associative Searchable Encryption by Using Hash Function

摘要

Combining the concept of PEKS and IBE, the Identity-Based Encryption with Keyword Search (IBEKS) has been proposed. In IBEKS scheme, trapdoors which can search a ciphertext are specified by the identity of the ciphertext like IBE. If a trapdoor satisfies the search condition specified in a ciphertext and the keyword associated with the trapdoor is equal to that of the ciphertext, then the trapdoor can search the ciphertext. In IBEKS scheme, if you want to search n different 005 with the same condition, you should make n trapdoors and query to the server n times. To reduce the computational cost of generating trapdoors of searcher and the communication cost between the server and the searcher, we propose associative keyword searchable encryption (AKSE). In AKSE, once the server receives a trapdoor from a searcher as search query, the server can generate new trapdoors with the same search condition associated with the trapdoor for different 005 and conduct search on the ciphertexts. Thus, the computational cost of generating trapdoors of searcher and the communication cost between the server and the searcher can be reduced. In this paper, we concentrate on constructing AKSE scheme. We consider that the computational cost should be low for practical use and intend to construct AKSE scheme from a cryptographic scheme which has low computational cost in a simple way. For constructing AKSE, we use key-policy attribute-based encryption (KP-ABE) scheme. We show a transformation from KP-ABE scheme into AKSE scheme and prove the security of AKSE schemes transformed from KP-ABE schemes.