Cryptography

Keeping the wolves out of wolfSSL

Trail of Bits is publicly disclosing four vulnerabilities that affect wolfSSL: CVE-2022-38152, CVE-2022-38153, CVE-2022-39173, and CVE-2022-42905. The four issues, which have CVSS scores ranging from medium to critical, can all result in a denial of service (DoS). These vulnerabilities have been discovered automatically using the novel protocol fuzzer tlspuffin. This blog post […]

Specialized Zero-Knowledge Proof failures

Zero-knowledge (ZK) proofs are useful cryptographic tools that have seen an explosion of interest in recent years, largely due to their applications to cryptocurrency. The fundamental idea of a ZK proof is that a person with a secret piece of information (a cryptographic key, for instance) can prove something about the secret […]

We sign code now

William Woodruff
Sigstore announced the general availability of its free and ecosystem-agnostic software signing service two weeks ago, giving developers a way to sign, verify and protect their software projects and the dependencies they rely on. Trail of Bits is absolutely thrilled to be a part of the project, and we spoke about our […]

It pays to be Circomspect

Fredrik Dahlgren, Staff Security Engineer
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 […]

Themes from Real World Crypto 2022

William Woodruff
Last week, over 500 cryptographers from around the world gathered in Amsterdam for Real World Crypto 2022, meeting in person for the first time in over two years. As in previous years, we dispatched a handful of our researchers and engineers to attend the conference, listen to talks, and schmooze observe the […]

Amarna: Static analysis for Cairo programs

Filipe Casal, fcasal
We are open-sourcing Amarna, our new static analyzer and linter for the Cairo programming language. Cairo is a programming language powering several trading exchanges with millions of dollars in assets (such as dYdX, driven by StarkWare) and is the programming language for StarkNet contracts. But, not unlike other languages, it has its […]

The Frozen Heart vulnerability in PlonK

Jim Miller
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 […]

The Frozen Heart vulnerability in Bulletproofs

Jim Miller
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, […]

The Frozen Heart vulnerability in Girault’s proof of knowledge

Jim Miller
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 […]

Coordinated disclosure of vulnerabilities affecting Girault, Bulletproofs, and PlonK

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. […]

Part 2: Improving crypto code in Rust using LLVM’s optnone

Henrik Brodin
Let’s implement crypto! Welcome to the second part of our posts on the challenges of implementing constant-time Rust code. Part 1 discussed challenges with constant-time implementations in Rust and WebAssembly and how optimization barriers can mitigate risk. The Rust crypto community has responded with several approaches, and in this post, we will […]

Part 1: The life of an optimization barrier

Fredrik Dahlgren
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 […]

Disclosing Shamir’s Secret Sharing vulnerabilities and announcing ZKDocs

Filipe Casal, Jim Miller
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 […]

Serving up zero-knowledge proofs

Jim Miller
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 […]