Secure Outsourced Computation in a Multi-tenant Cloud

We present a general-purpose protocol that enables a client to delegate the computation of any function to a cluster of n machines in such a way that no adversary that corrupts at most n − 1 machines can recover any information about the client’s input or output. The protocol makes black-box use of multi-party computation (MPC) and secret sharing and inherits the security properties of the underlying MPC protocol (i.e., passive vs. adaptive security and security in the presence of a semi-honest vs. malicious adversary). Using this protocol, a client can securely delegate any computation to a multi-tenant cloud so long as the adversary is not co-located on at least one machine in the cloud. Alternatively, a client can use our protocol to securely delegate its computation to multiple multi-tenant clouds so long as the adversary is not co-located on at least one machine in one of the clouds.