Batch verifiable computation with public verifiability for outsourcing polynomials and matrix computations

In a verifiable computation (VC) scheme, a client asks a server to perform some outsourced computations, and the latter returns the results as its response. The results can be verified privately or publicly. Fiore and Gennaro (CCS 2012) constructed publicly verifiable protocols for secure outsourcing polynomials andmatrix computations. Batch verifiable computation (BVC) schemes allow a client to outsource multiple functions on a same input, and thus much reduce the storage overhead at the server side without sacrificing the efficiency of verification. However, existing BVC schemes only support private verifiability (which only allows the client who outsources the computations to verify the results). In this paper, we propose BVC schemes with public verifiability, i.e., any third party can efficiently verify the results returned by the server without accessing secret key. To delegate s functions, our BVC schemes require a cloud storage of only 1 + 1/s times the storage size needed by the s functions themselves. We extend our schemes to meet less cloud storage overhead as well.