Abstract: In order to realize fine granularity access control and multiple keyword data search, this paper introduces access tree and strong one-time signature, and proposes a conditional proxy re-encryption scheme which can be used for multiple keyword search. Compared with the existing schemes, this scheme has obvious improvement in computational efficiency. The scheme can resist the selective cipher-text attack and satisfy the security of the chosen cipher-text attack under the random prophet model. The scheme proposed in this paper plays an important role in solving the security problem of sensitive data in industries such as finance.

Key words:  keyword search, proxy re-encryption, access tree, data security