Cryptography

Our crypto experts answer 10 key questions

Justin Jacob
Cryptography is a fundamental part of electronics and the internet that helps secure credit cards, cell phones, web browsing (fingers crossed you’re using TLS!), and even top-secret military data. Cryptography is just as essential in the blockchain space, with blockchains like Ethereum depending on hashes, Merkle trees, and ECDSA signatures, among other […]

Announcing AES-GEM (AES with Galois Extended Mode)

Scott Arciszewski
Today, AES-GCM is one of two cipher modes used by TLS 1.3 (the other being ChaCha20-Poly1305) and the preferred method for encrypting data in FIPS-validated modules. But despite its overwhelming success, AES-GCM has been the root cause of some catastrophic failures: for example, Hanno Böck and Sean Devlin exploited nonce misuse to […]

Quantum is unimportant to post-quantum

Opal Wright
You might be hearing a lot about post-quantum (PQ) cryptography lately, and it’s easy to wonder why it’s such a big deal when nobody has actually seen a quantum computer. But even if a quantum computer is never built, new PQ standards are safer, more resilient, and more flexible than their classical […]

Disarming Fiat-Shamir footguns

Opal Wright
The Fiat-Shamir transform is an important building block in zero-knowledge proofs (ZKPs) and multi-party computation (MPC). It allows zero-knowledge proofs based on interactive protocols to be made non-interactive. Essentially, it turns conversations into documents. This ability is at the core of powerful technologies like SNARKs and STARKs. Useful stuff! But the Fiat-Shamir […]

Themes from Real World Crypto 2024

Trail of Bits
In March, Trail of Bits engineers traveled to the vibrant (and only slightly chilly) city of Toronto to attend Real World Crypto 2024, a three-day event that hosted hundreds of brilliant minds in the field of cryptography. We also attended three associated events: the Real World Post-Quantum Cryptography (RWPQC) workshop, the Fully Homomorphic Encryption (FHE) […]

Announcing two new LMS libraries

Will Song
The Trail of Bits cryptography team is pleased to announce the open-sourcing of our pure Rust and Go implementations of Leighton-Micali Hash-Based Signatures (LMS), a well-studied NIST-standardized post-quantum digital signature algorithm. If you or your organization are looking to transition to post-quantum support for digital signatures, both of these implementations have been […]

Cryptographic design review of Ockam

Joop van de Pol, Marc Ilunga, Jim Miller, Fredrik Dahlgren
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 […]

Circomspect has been integrated into the Sindri CLI

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 […]

Breaking the shared key in threshold signature schemes

Fredrik Dahlgren
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 […]

Cloud cryptography demystified: Amazon Web Services

Scott Arciszewski
This post, part of a series on cryptography in the cloud, provides an overview of the cloud cryptography services offered within Amazon Web Services (AWS): when to use them, when not to use them, and important usage considerations. Stay tuned for future posts covering other cloud services. At Trail of Bits, we […]

Chaos Communication Congress (37C3) recap

Trail of Bits
Last month, two of our engineers attended the 37th Chaos Communication Congress (37C3) in Hamburg, joining thousands of hackers who gather each year to exchange the latest research and achievements in technology and security. Unlike other tech conferences, this annual gathering focuses on the interaction of technology and society, covering such topics as politics, entertainment, […]

We build X.509 chains so you don’t have to

For the past eight months, Trail of Bits has worked with the Python Cryptographic Authority to build cryptography-x509-verification, a brand-new, pure-Rust implementation of the X.509 path validation algorithm that TLS and other encryption and authentication protocols are built on. Our implementation is fast, standards-conforming, and memory-safe, giving the Python ecosystem a modern […]

Celebrating our 2023 open-source contributions

At Trail of Bits, we pride ourselves on making our best tools open source, such as Slither, PolyTracker, and RPC Investigator. But while this post is about open source, it’s not about our tools… In 2023, our employees submitted over 450 pull requests (PRs) that were merged into non-Trail of Bits repositories. This demonstrates our […]

Tag, you’re it: Signal tagging in Circom

Tjaden Hess
We at Trail of Bits perform security reviews for a seemingly endless stream of applications that use zero-knowledge (ZK) proofs. While fast new arithmetization and folding libraries like Halo2, Plonky2, and Boojum are rapidly gaining adoption, Circom remains a mainstay of ZK circuit design. We’ve written about Circom safety before in the […]