## Cryptology ePrint Archive: Report 2020/270

Practical Predicate Encryption for Inner Product

Yi-Fan Tseng and Zi-Yuan Liu and Raylin Tso

Abstract: Inner product encryption is a powerful cryptographic primitive, where a private key and a ciphertext are both associated with a predicate vector and an attribute vector, respectively. A successful decryption requires the inner product of the predicate vector and the attribute vector to be zero. Most of the existing inner product encryption schemes suffer either long private key or heavy decryption cost. In this manuscript, an efficient inner product encryption is proposed. The length for a private key is only an element in $\mathbb{G}$ and an element in $\mathbb{Z}_p$. Besides, only a pairing is needed for decryption. Moreover, both formal security proof and implementation result are demonstrated in this manuscript. To the best of our knowledge, our scheme is the most efficient one in terms of the private key length and the number of pairings for decryption.

Category / Keywords: public-key cryptography / Predicate Encryption, Inner Product Encryption, Constant-size Private Key, Efficient Decryption, Constant Pairing Computations