A Fast and Verified Software Stack for Secure Function Evaluation

Abstract

We present a high-assurance software stack for secure function evaluation (SFE). Our stack consists of three components: i. a verified compiler (CircGen) that translates C programs into Boolean circuits; ii. a verified implementation of Yao's SFE protocol based on garbled circuits and oblivious transfer; and iii. transparent application integration and communications via FRESCO, an open-source framework for secure multiparty computation (MPC). CircGen is a general purpose tool that builds on CompCert, a verified optimizing compiler for C. It can be used in arbitrary Boolean circuit-based cryptography deployments. The security of our SFE protocol implementation is formally verified using EasyCrypt, a tool-assisted framework for building high-confidence cryptographic proofs, and it leverages a new formalization of garbled circuits based on the framework of Bellare, Hoang, and Rogaway (CCS 2012). We conduct a practical evaluation of our approach, and conclude that it is competitive with state-of-the-art (unverified) approaches. Our work provides concrete evidence of the feasibility of building efficient, verified, implementations of higher-level cryptographic systems. All our development is publicly available.

New Primitives for Actively-Secure MPC over Rings with Applications to Private Machine Learning

“…We implement the online phase in FRESCO [22], an active open-source Java framework for MPC with a strong track record [14], [40]. We chose FRESCO as it offers an accessible API-based approach for writing MPC applications.…”

$$\textsc {Wys}^\star $$ : A DSL for Verified Secure Multi-party Computations

“…Verified MPC toolchain. Almeida et al [4] build a verified toolchain consisting of (a) a verified circuit compiler from (a subset of) C to boolean circuits, and (b) a verified implementation of Yao's [64] garbled circuits protocol for 2-party MPC. They use CompCert [36] for the former, and EasyCrypt [11] for the latter.…”

“…To prove the interpreter behaves correctly, we prove, in F , that it correctly implements the formalized distributed semantics. The circuit library and the GMW implementation are not verified-while it is possible to verify the circuit library [4], verifying a GMW implementation is an open research question. But the stage is set for verified versions to be plugged into the Wys codebase.…”

A Machine-Checked Proof of Security for AWS Key Management Service

“…AWS KMS, a core component of the AWS cloud, lets AWS customers create and manage encryption keys, providing a consistent view of encryption/decryption operations across AWS services, and controlling their use through AWS Identity and Access Management (IAM). 1 The widespread usage of AWS KMS and the central role of the DMP justifies a high-assurance security proof, leveraging recent developments in computer-aided cryptography such as [3,4,7].…”