Raziel: Private and Verifiable Smart Contracts on Blockchains

TL;DR

Raziel integrates secure multi-party computation and proof-carrying code to enhance privacy, correctness, and verifiability in blockchain smart contracts, effectively preventing attacks and enabling third-party validation without revealing sensitive data.

Contribution

This paper introduces Raziel, a novel framework combining MPC and proof-carrying code for private, verifiable smart contracts with practical implementation and incentive mechanisms.

Findings

Successfully prevents DAO and Gyges attacks

Demonstrates practical viability with real-world examples

Enables third-party verification via Zero-Knowledge Proofs

Abstract

Raziel combines secure multi-party computation and proof-carrying code to provide privacy, correctness and verifiability guarantees for smart contracts on blockchains. Effectively solving DAO and Gyges attacks, this paper describes an implementation and presents examples to demonstrate its practical viability (e.g., private and verifiable crowdfundings and investment funds). Additionally, we show how to use Zero-Knowledge Proofs of Proofs (i.e., Proof-Carrying Code certificates) to prove the validity of smart contracts to third parties before their execution without revealing anything else. Finally, we show how miners could get rewarded for generating pre-processing data for secure multi-party computation.