Jim Miller - The Trail of Bits Blog

A retrospective on the $100M Balancer hack that occurred in November 2025, including long-term, strategic guidance on how to avoid similar bugs.

The release of Bitchat last week was met with a mixture of glowing praise and sharp criticism. Both extremes bear some truth, but they also miss the mark and reveal gaps in how we discuss security in emerging products.

In October 2023, we audited Silence Laboratories’ DKLs23 threshold signature scheme (TSS) library—one of the first production implementations of this then-novel protocol that uses oblivious transfer (OT) instead of traditional Paillier cryptography. Our review uncovered serious flaws that could enable key destruction attacks, which Silence Laboratories promptly fixed.

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 […]

Our tool Circomspect is now integrated into the Sindri command-line interface (CLI)! We designed Circomspect to help developers build Circom circuits more securely, particularly given the limited tooling support available for this novel programming framework. Integrating this tool into a development environment like that provided by Sindri is a significant step toward […]

We’ve updated ZKDocs with four new sections and additions to existing content. ZKDocs provides explanations, guidance, and documentation for cryptographic protocols that are otherwise sparingly discussed but are used in practice. As such, we’ve added four new sections detailing common protocols that previously lacked implementation guidance: The Inner Product Argument (IPA), which […]

The US government recently issued a request for information (RFI) about open-source software (OSS) security. In this blog post, we will present a summary of our response and proposed solutions. Some of our solutions include rewriting widely used legacy code in memory safe languages such as Rust, funding OSS solutions to improve […]

TL;DR: We identified 11 security vulnerabilities in YOLOv7, a popular computer vision framework, that could enable attacks including remote code execution (RCE), denial of service, and model differentials (where an attacker can trigger a model to perform differently in different contexts). Open-source software […]

We discovered a critical vulnerability in Incognito Chain that would allow an attacker to mint arbitrary tokens and drain user funds. Incognito offers confidential transactions through zero-knowledge proofs, so an attacker could have stolen millions of dollars of shielded funds without ever being detected or identified. The vulnerability stemmed from an insecure […]

In part 1 of this blog post, we disclosed critical vulnerabilities that break the soundness of multiple implementations of zero-knowledge proof systems. This class of vulnerability, which we dubbed Frozen Heart, is caused by insecure implementations of the Fiat-Shamir transformation that allow malicious users to forge proofs for random statements. In part […]

In part 1 of this series, we disclosed critical vulnerabilities that break the soundness of multiple implementations of zero-knowledge proof systems. This class of vulnerability, which we dubbed Frozen Heart, is caused by insecure implementations of the Fiat-Shamir transformation that allow malicious users to forge proofs for random statements. In part 2, […]

In part 1 of this series, we disclosed critical vulnerabilities that break the soundness of multiple implementations of zero-knowledge proof systems. This class of vulnerability, which we dubbed Frozen Heart, is caused by insecure implementations of the Fiat-Shamir transformation that allow malicious users to forge proofs for random statements. The vulnerability is […]

Trail of Bits is publicly disclosing critical vulnerabilities that break the soundness of multiple implementations of zero-knowledge proof systems, including PlonK and Bulletproofs. These vulnerabilities are caused by insecure implementations of the Fiat-Shamir transformation that allow malicious users to forge proofs for random statements. We’ve dubbed this class of vulnerabilities Frozen Heart. […]

Trail of Bits is publicly disclosing two bugs that affect Shamir’s Secret Sharing implementation of Binance’s threshold signature scheme library (tss-lib) and most of its active forks. Here is the full list of affected repositories: Binance’s tss-lib Clover Network’s threshold-crypto Keep Network’s keep-ecdsa Swingby’s tss-lib THORchain’s tss-lib ZenGo X’s […]

Zero-knowledge (ZK) proofs are gaining popularity, and exciting new applications for this technology are emerging, particularly in the blockchain space. So we’d like to shine a spotlight on an interesting source of implementation bugs that we’ve seen—the Fiat Shamir transformation. A ZK proof can be either interactive, where the […]

The elliptic curve digital signature algorithm (ECDSA) is a common digital signature scheme that we see in many of our code reviews. It has some desirable properties, but can also be very fragile. For example, LadderLeak was published just a couple of weeks ago, which demonstrated the feasibility of key recovery with a side channel […]

Over 642 brilliant cryptographic minds gathered for Real World Crypto 2020, an annual conference that brings together cryptographic researchers with developers implementing cryptography in the wild. Overall, RWC 2020 was an impressive conference that demonstrated some amazing work. Here we explore three major themes that emerged: Crypto bugs are everywhere…Whether it’s a somewhat unsurprising Bleichenbacher […]

During my internship this summer, I built a multi-party computation (MPC) tool that implements a 3-party computation protocol for perceptron and support vector machine (SVM) algorithms. MPC enables multiple parties to perform analyses on private datasets without sharing them with each other. I defveloped a technique that lets three parties obtain the results of machine […]