In November 2023, Aleo engaged NCC Group’s Cryptography Services team to perform a review of the consensus mechanism implemented by snarkOS: “a decentralized operating system for zero-knowledge applications [that] forms the backbone of Aleo network, which verifies transactions and stores the encrypted state applications in a publicly verifiable manner.” The consensus mechanism is based on a partially synchronous version of the Bullshark Byzantine Fault Tolerance (BFT) protocol, which uses a directed acyclic graph (DAG) to order updates. The review was performed remotely by four consultants over a total of 25 person-days of effort. A retest was performed in January 2024.

This review complements NCC Group’s prior public report reviewing Aleo’s snarkVM.