After a peer review process, the scientific publication entitled “ZEKRA: Zero-Knowledge Control-Flow Attestation” has been accepted for presentation at the 18th ACM ASIA Conference on Computer and Communications Security (ACM ASIACCS 2023) that is held in Melbourne Australia from July 10th to July 14th, 2023. In this work, UBITECH’s Dr Thanassis Giannetsos (Head, Digital Security & Trusted Computing Research Group) and his co-authors propose a novel method of encasing a program-agnostic execution path verification task inside an arithmetic circuit whose correct execution can be verified by untrusted verifiers using a zero-knowledge proof system without the verifiers learning any secret inputs.
In particular, they propose a novel protocol called ZEro-Knowledge contRol-flow Attestation (ZEKRA), which is, to their knowledge, the first privacy-preserving Control-Flow Attestation (CFA) protocol. Without imposing additional prover assumptions, they remove all trust and complexity assumptions regarding verifiers by outsourcing attestation verifications to intermediate workers who employ VC to convince verifiers about the verification results.
Their work offers the following contributions: (i) they present a novel scheme that lets underpowered provers convince untrusted verifiers about a program’s correct execution in zero-knowledge by offloading the verification to an intermediate worker that assures verifiers about the result without disclosing any secrets using zkSNARK technology; (ii) they detail their outsourceable circuit design, including the use of several circuit optimization techniques; (iii) Realistic case studies, showing how ZEKRA can resolve privacy issues in privacy-sensitive (non-time-critical) application domains; and, (iv) they validate and benchmark ZEKRA with a proof-of-concept implementation, which they make publicly available to ensure reproducibility and encourage further work.
