Attribute-Based Encryption for Restricted Circuits from Lattices

This paper defines a kind of restricted circuits with polynomially 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(omega)(x) = 1 then for all the OR gates in the sub-circuit f(omega), its first or left incoming wire will evaluate to 1, where f(omega) denotes a sub-circuit with root node omega in circuit f(omega) Moreover, this paper proves that the scheme is secure against chosen plaintext attack in the selective model under the learning with errors (LWE) assumptions.