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. […]
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 […]
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 […]
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 […]
Zero-knowledge proofs, once a theoretical curiosity, have recently seen widespread deployment in blockchain systems such as Zcash and Monero. However, most blockchain applications of ZK proofs make proof size and performance tradeoffs that are a poor fit for other use-cases. In particular, these protocols often require an elaborate trusted setup phase and optimize for proof […]
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 […]
OpenSSL is one of the most popular cryptographic libraries out there; even if you aren’t using C/C++, chances are your programming language’s biggest libraries use OpenSSL bindings as well. It’s also notoriously easy to mess up due to the design of its low-level API. Yet many of these mistakes fall into […]
TL;DR: We’ve open-sourced a new library, μthenticode, for verifying Authenticode signatures on Windows PE binaries without a Windows machine. We’ve also integrated it into recent builds of Winchecksec, so that you can use it today to verify signatures on your Windows executables! As a library, μthenticode aims to be a breeze to integrate: It’s written […]
We, along with our partner Matthew Green at Johns Hopkins University, are using zero-knowledge (ZK) proofs to establish a trusted landscape in which tech companies and vulnerability researchers can communicate reasonably with one another without fear of being sabotaged or scorned. Over the next four years, we will push the state of the art in […]
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 […]
On Tuesday, the NSA announced they had found a critical vulnerability in the certificate validation functionality on Windows 10 and Windows Server 2016/2019. This bug allows attackers to break the validation of trust in a wide variety of contexts, such as HTTPS and code signing. Concerned? Get the important details and see if you’re vulnerable […]
Recently, security researchers discovered that Apple was sending safe browsing data to Tencent for all Chinese users. This revelation has brought the underlying security and privacy guarantees of the safe browsing protocol under increased scrutiny. In particular, safe browsing claims to protect users by providing them with something called k-anonymity. In this post we’ll show […]
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 […]
This year’s IACR Crypto conference was an excellent blend of far-out theory and down-to-earth pragmatism. A major theme throughout the conference was the huge importance of getting basic cryptographic primitives right. Systems ranging from TLS servers and bitcoin wallets to state-of-the-art secure multiparty computation protocols were broken when one small sub-component was either chosen poorly […]
As a summer intern at Trail of Bits, I’ve been working on building Fennec, a tool to automatically replace function calls in compiled binaries that’s built on top of McSema, a binary lifter developed by Trail of Bits. The Problem Let’s say you have a compiled binary, but you […]
Broadly, an end-to-end encrypted messaging protocol is one that ensures that only the participants in a conversation, and no intermediate servers, routers, or relay systems, can read and write messages. An end-to-end encrypted group messaging protocol is one that ensures this for all participants in a conversation of three or more people. End-to-end encrypted group […]
Here at Trail of Bits we review a lot of code. From major open source projects to exciting new proprietary software, we’ve seen it all. But one common denominator in all of these systems is that for some inexplicable reason people still seem to think RSA is a good cryptosystem to use. Let me save […]
RandomX is a new ASIC and GPU-resistant proof-of-work (PoW) algorithm originally developed for Monero, but potentially useful in any blockchain using PoW that wants to bias towards general purpose CPUs. Trail of Bits was contracted by Arweave to review this novel algorithm in a two person-week engagement and provide guidance on alternate parameter selection. But […]
Trail of Bits has released Indurative, a cryptographic library that enables authentication of a wide variety of data structures without requiring users to write much code. Indurative is useful for everything from data integrity to trustless distributed systems. For instance, developers can use Indurative to add Binary Transparency to a package manager — so users […]
For my winternship and springternship at Trail of Bits, I researched novel techniques for symbolic execution on cryptographic protocols. I analyzed various implementation-level bugs in cryptographic libraries, and built a prototype Manticore-based concolic unit testing tool, Sandshrew, that analyzed C cryptographic primitives under a symbolic and concrete environment. Sandshrew is a first step […]
TLS 1.3 represents the culmination of over two decades of experience in deploying large-scale transport security. For the most part it simplifies and improves the security of TLS and can act as a drop-in replacement for TLS 1.2. However, one new feature in the protocol represents a significant security risk to some existing applications: TLS […]
This year for CSAW CTF, Trail of Bits contributed two cryptography problems. In the first problem, you could combine two bugs to break DSA much like the Playstation 3 firmware hackers. The other challenge–-weirder and mathier–-was split into two parts: one for the qualifiers, one in finals. This challenge, “Holywater,” was some of the most fun I’ve ever had making a CTF problem.
The Trail of Bits cryptographic services team contributed two cryptography CTF challenges to the recent CSAW CTF. Today we’re going to cover the easier one, titled “Disastrous Security Apparatus – Good luck, ‘k?” This problem involves the Digital Signature Algorithm (DSA) and the way an apparently secure algorithm can be made entirely insecure through surprising […]
Building and using cryptographic libraries is notoriously difficult. Even when each component of the system has been implemented correctly (quite difficult to do), improperly combining these pieces can lead to disastrous results. Cryptography, when rolled right, forms the bedrock of any secure application. By combining cutting-edge mathematics and disciplined software engineering, modern crypto-systems guarantee data and communication privacy.
