Riad Wahby: 2017 Security Workshop


Monday, April 10, 2017
Location: McCaw Hall, Arrillaga Alumni Center

"Full accounting for verifiable outsourcing "



Systems for verifiable outsourcing incur costs for a prover, a verifier, and precomputation; outsourcing makes sense when these costs are cheaper than not outsourcing. Yet, prover costs are generally ignored; only Verifiable ASICs (VA), wherein the prover and verifier are custom chips, accounts for these. Unfortunately, VA assumes away the cost of precomputation. This paper describes a system that works in the VA setting, called Giraffe; charges for all three costs; and identifies regimes where outsourcing is worthwhile. Giraffe is based on an interactive proof geared to data parallel computation. Giraffe refines this protocol to achieve asymptotic optimality for the prover, develops a design template that produces hardware designs automatically for a wide range of parameters, introduces hardware primitives molded to the protocol's data flows, and incorporates program transformation techniques that expand applicability. Giraffe wins even when outsourcing several tens of sub-computations, scales to 500x larger computations than prior work, and can profitably outsource parts of programs that are not otherwise worthwhile to outsource.

Joint work with Ye Ji, Andrew J. Blumberg, Abhi Shelat, Justin Thaler, Michael Walfish, Thomas Wies


Riad S. Wahby is a second-year Ph.D. student at Stanford, advised by David Mazières and Keith Winstein. He was previously a junior research scientist at the Courant Institute at NYU, working with Michael Walfish on verifiable computation, cryptographic hardware, and operating systems security; and he spent ten years as an analog and mixed-signal integrated circuit designer at Silicon Laboratories in Austin, TX. Riad graduated from MIT in 2004 with an S.B. and M.Eng. in Electrical Engineering and Computer Science.