Research on Non-interactive Construction based on Fuzzy Conditional Proxy Re-encryption

In a conditional proxy re-encryption (C-PRE) scheme, a semi-trusted proxy can transform Alice’s ciphertext into Bob’s ciphertext without learning the underlying plaintext, if the ciphertext satisfies a certain condition. To achieve more fine-grained delegation on conditions, Fang, Wang and Ge introduced the notion of fuzzy conditional proxy re-encryption (FC-PRE), whereby the conditions is viewed a set of descriptive keywords. The proxy with a re-encryption key for a condition word set can convert a ciphertext encrypted with a condition word set , if and only if and are close to each other as measured by the "set overlap" distance metric. Nonetheless, they left an open problem on how to construct a non-interactive FC-PRE scheme. Furthermore, their scheme is only proved secure in the random oracle model. In this paper, we answer the above problems affirmatively by presenting a non-interactive fuzzy conditional proxy reencryption scheme. Moreover, our scheme is proved secure without random oracles.