Fredrik Dahlgren

Over two audits in 2023, we reviewed a blockchain system developed by Axiom that allows computing over the entire history of Ethereum, all verified by zero-knowledge proofs (ZKPs) on-chain using ZK-verified elliptic curve and SNARK recursion operations. This system is built using the Halo2 framework—a complex, emerging technology that presents many challenges when building a secure application, including potential under-constrained issues resulting from its low-level API.

In October 2023, Ockam hired Trail of Bits to review the design of its product, a set of protocols that aims to enable secure communication (i.e., end-to-end encrypted and mutually authenticated channels) across various heterogeneous networks. A secure system starts at the design […]

Today we are disclosing a denial-of-service vulnerability that affects the Pedersen distributed key generation (DKG) phase of a number of threshold signature scheme implementations based on the Frost, DMZ21, GG20, and GG18 protocols. The vulnerability allows a single malicious participant to surreptitiously raise the threshold required to reconstruct the shared key, which […]

Today we are announcing the latest addition to the Trail of Bits Testing Handbook: a brand new chapter on CodeQL! CodeQL is a powerful and versatile static analysis tool, and at Trail of Bits, we regularly use CodeQL on client engagements to find common vulnerabilities and to perform variant analysis for already […]

TL;DR: We have released version 0.8.0 of Circomspect, our static analyzer and linter for Circom. Since our initial release of Circomspect in September 2022, we have added five new analysis passes, support for tags, tuples, and anonymous components, links to in-depth descriptions of each identified issue, and squashed a […]

In October 2019, a security researcher found a devastating vulnerability in Tornado.cash, a decentralized, non-custodial mixer on the Ethereum network. Tornado.cash uses zero-knowledge proofs (ZKPs) to allow its users to privately deposit and withdraw funds. The proofs are supposed to guarantee that each withdrawal can be matched against a […]

Many engineers choose Rust as their language of choice for implementing cryptographic protocols because of its robust security guarantees. Although Rust makes safe cryptographic engineering easier, there are still some challenges to be aware of. Among them is the need to preserve constant-time properties, which ensure that, regardless of the input, code […]

One of your developers finds a bug in your codebase—an unhandled error code—and wonders whether there could be more. He combs through the code and finds unhandled error after unhandled error. One lone developer playing whack-a-mole. It’s not enough. And your undisciplined team of first-year Stanford grads never learned software engineering. You’re […]