Two-Round Oblivious Linear Evaluation from Learning with Errors
Oblivious Linear Evaluation (OLE) is a simple yet powerful cryptographic primitive which allows a sender, holding an affine function f(x) = a + bx over a finite field, to let a receiver learn f(w) for a w of the receiver’s choice. In terms of security, the sender remains oblivious of the receiver’s input w, whereas the receiver learns nothing beyond f(w) about f . In recent years, OLE has emerged as an essential building block to construct efficient, reusable and maliciously-secure two-party computation. In this work, we present efficient two-round protocols for OLE based on the Learning with Errors (LWE) assumption. Our first protocol for OLE is secure against malicious unbounded receivers and semi-honest senders. The receiver’s first message may carry information about a batch of inputs, and not just a single input. We then show how we can extend the above protocol to provide malicious security for both parties.