Sam is a Research Partner at Paradigm, focused on portfolio companies and research into security and related topics. Previously, Sam was a security engineer at Trail of Bits where he worked on improving security tooling for developers and helped clients write safer code. Sam helps secure the cryptocurrency ecosystem by responsibly disclosing vulnerabilities and publishing educational resources.

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samczsun

Research Partner

I like challenging assumptions. I like trying to do the impossible, finding what others have missed, and blowing people's minds with things they never saw coming.

Hiding in Plain Sight

It only takes one vulnerability to cause serious financial damage to hundreds if not thousands of innocent users. Breaking down how I found and helped patch a vulnerability that put over 109k ETH at risk.

Two Rights Might Make A Wrong

If you work in software engineering, odds are you've heard of at least one software engineering principle. While I wouldn't advocate for religiously following every principle to the letter, there are a few that are really worth paying attention to.

The Dangers of Surprising Code

This is the second in a series of blog posts about bugs I've found in go-ethereum (Geth). If you haven't already, take a look at Part 1 here. Today's post is about a bug

Booby Trapping the Ethereum Blockchain

Uncovering a Four Year Old Bug

Paradigm CTF 2021 took place in early February and together, players solved all but two of the challenges during the competition (and one of the remaining two mere days later). We're taking a look at the "swap" challenge in the form of a guided walkthrough.

Paradigm CTF 2021 - swap

This is the first in a series of blog posts about the bugs I've found in go-ethereum (Geth), the official Golang implementation of the Ethereum protocol. While you don't need a deep understanding of Geth in order to follow these blog posts, knowledge of how Ethereum itself works will be helpful.

This first post is about a bug in Geth's uncle validation routine which did not behave correctly given a specially crafted uncle. If exploited, this could have caused an accidental fork between Geth and Parity nodes.

The Block Mined In January, 584942419325

Everything you need to know about price oracles and how to use them safely.

So you want to use a price oracle

samczsun joins Paradigm as a Research Partner.

Changing Lanes

On September 15, 2020, a small group of people worked through the night to rescue over 9.6MM USD from a vulnerable smart contract. This is our story.