Generalized homomorphic MACs with efficient verification

Homomorphic MACs allow the holder of a secret key to construct authenticators for data blocks such that an untrusted server that computes a function of the data, can also compute an authenticator that can be verified by the key holder, guaranteeing correctness of the computation. Homomorphic MACs that allow verifiable computation of multivariate polynomials of degree ≤ 2 have been proposed by Backes, Fiore and Reischuk (CCS 2013). We generalize their construction such that polynomials of degree l>2 can also be computed. Our generalization uses multilinear map abstraction and has security based on the l-linear assumption.