Attribute-Based Encryption for Restricted Circuits from Lattices

This paper defines a kind of restricted circuits with polynomials bounded depth and proposes a key-policy attribute-based encryption (KP-ABE) scheme for those restricted circuits from lattices. And the secret keys in our scheme are shorter than in previous scheme. Specifically the restricted circuit f means that for any input x, if f_ω(X) = 1 then for all the OR gates in the sub-circuit f_ω, its first or left incoming wire will evaluate to 1, where f_ω denotes a sub-circuit with root node ω in circuit f. Moreover, this paper proves that the scheme is secure against chosen plaintext attack in the selective model under the learning with errors (LWE) assumptions.