Security research (https://xitter.cf/t.co/xrmvhFVPtv), EDM (https://xitter.cf/t.co/Ynq2DNWQa1), & board member @ Zcash Foundation.
Calgary, Canada
Joined February 2012
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Taylor Hornby 🛡❤️ retweeted
Some stats on #php2shell. In the 10 hours before it was publicly announced, across the @Cloudflare network we saw thousands of attempts to exploit it. That jumped to tens of thousands in the 45 minutes post announcement, hundreds of thousands within 2 hours, and millions now.
Taylor Hornby 🛡❤️ retweeted
This is the first time I've ever seen a site do this, the obvious simple response to a disclosure of a vulnerability without a fix: sacrifice availability to preserve safety. This option should be why we do full disclosure.
Taylor Hornby 🛡❤️ retweeted
Yesterday the Zcash Foundation board named me Executive Director. Thank you to Alex for steady leadership through a tumultuous stretch, and to everyone who has reached out this week.
The job as I see it has two halves: 1) keep the infrastructure fast, secure, and boring. 2) make privacy something ordinary people use without having to think about it.
I don’t think privacy is a feature, and I don’t think it’s a niche. It’s the room a society needs to think, speak, associate, and change its mind. Any system people depend on for daily life should give them that room by default. That’s the standard I’ll hold our work to.
Taylor Hornby 🛡❤️ retweeted
Big milestone for Shielded Labs: the activation height for NU7 is being set today! The upgrade includes our first major mainnet deployment: the Network Sustainability Mechanism (NSM).
Like Bitcoin, Zcash faces a long-term challenge: how to sustain network security as block rewards decline. The NSM helps address that while preserving the 21 million coin cap.
ZIP-235 removes 60% of transaction fees from circulation, allowing that ZEC to be reissued as future block rewards. ZIP-237 starts that recycling around February 2031.
At current fee levels, that’s only about 210 ZEC per year. This is a modest first step, but we’re optimistic about how new use cases for the NSM could evolve over time and contribute to Zcash’s long-term security.
Taylor Hornby 🛡❤️ retweeted
The Zcash Foundation Board of Directors has appointed David Campbell as Executive Director.
Thank you, Alex Bornstein, for leading with a constant focus on bringing the Zcash ecosystem together. Welcome, David, a longtime member of this community.
zfnd.org/zcash-foundation-na…
Taylor Hornby 🛡❤️ retweeted
Think about the chain of human decisions that’s involved in upgrading a big network full of hardware devices made by different vendors. Now think about how accessing that same network looks from the offensive side right now. It’s not even close to symmetrical.
Taylor Hornby 🛡❤️ retweeted
CLAUDE FOUND THE SEEDS
anthropic.com/research/ecdsa…
Taylor Hornby 🛡❤️ retweeted
shielded pools *do not* provide high levels of privacy if you use them as a pass through
"pass through" means you move funds into a pool and then withdraw them quickly after
shielded pools provide privacy if you hold funds at rest over a long period of time
Ledger theft, day two. Since yesterday the thief has pushed ether through Tornado Cash three times, and each time on into Zcash's shielded pool. We followed every lot out the far side. Here is how, step by step.
1. THE SAME BUILD, THREE TIMES
An ether wallet pays a fresh splitter. The splitter pays four fresh wallets. The four drop it into Tornado Cash's 100, 10 and 1 ETH pools. Minutes, every time.
Run 1, yesterday 15:17: 1,254 ETH. Run 2, today 09:42: 1,291 ETH. Run 3, today 11:56: 450 ETH from 0xfa4EaBB840A33C156E600311433AE261CBfCb0e2, in the pools by 12:15.
2. OUT OF TORNADO CASH
The mixer breaks the link between a deposit and a withdrawal. We do not need the link. Our tooling fingerprints the withdrawal transactions themselves: how each one is constructed, who constructs it, and when.
Yesterday's 65 withdrawals (1,084 ETH) and today's 96 (1,726 ETH) all carry the same signature. The six other withdrawals from those pools in today's windows do not. Run 3 came out from 12:18 into 0x0d697aa182801566d87adc86e68e95fd3b2f5f82 (213 ETH) and 0x676b16cc18542f37d202a1a79ac05463395496a4 (122 ETH), and 195 ETH of it was inside a cross-chain swap service by 12:38. Forty-two minutes, end to end.
3. INTO ZCASH, AND OUT AGAIN
The swap service turns the ether into shielded ZEC, where sender, amount and recipient vanish. But the service's own shielding of each lot is public, and from it we derive a value signature for that lot's exit, then scan every transparent exit from the pool. 108 of 108 exits across both days match their lot to the zatoshi. Not one other exit from the pool does.
First lot today: in at 10:18:18, out at 11:06:16 in block 3512847 (8d26a9b095d4d28373527f7a6eb81a3be7f906d1e2190960c0512ff64f369418 and 738c6d1261e79766e4dd16bdbd38dced91b8e3a86ce41dcda83eda1f19208fbf), straight into a ZEC to USDC order.
Today so far: 20 lots ordered (2,379 ZEC, $2.9m), 14 out, 5 inside the pool, 1 still settling. Every exit feeds a ZEC to USDC order paying two wallets born at 11:11, 22 of the 28 paid by 12:43:
0x816D5Ee17DB1495d1409F135b98FF3edc5F3cDf8: 940,561 USDC
0xBA736A4b616e79867B6d586293966b552883f3F3: 852,258 USDC
1.79m USDC, unspent. @Circle can freeze it.
(1/2) 🧵⤵️
Taylor Hornby 🛡❤️ retweeted
I don't think people understand how cool it is that Zcash is open to cutting-edge techniques like Formal Verification and Private Information Retrieval. It makes being part of the ecosystem feel fresh and exciting in ways that the AI age has degraded otherwise.
Taylor Hornby 🛡❤️ retweeted
And specifically for cryptanalysts who are working with models and for the labs:
Folks, what we need right now are *negative* results. Silence is the worst thing you could be publishing.
Taylor Hornby 🛡❤️ retweeted
"convert all 722 preprints into 3blue1brown videos. don't make mistakes."
Taylor Hornby 🛡❤️ retweeted
Everybody mathematical on my timeline is talking about what they see as the most marvelous result from the OpenAI knowledge dump. Shall we talk about which is the least marvelous? My candidate is #187, Snaky vs Breaker. It's a game played on an infinite chessboard. The players alternate coloring squares black and white. One player tries to make a particular pattern of six squares that looks like a snake. The other player tries to prevent that. It turns out that Snaky wins over Breaker in 21 moves. It's a tedious enumeration of thousands of cases, all of which are carefully spelled out in the paper. I read the paper; I don't think there are any important new techniques in it. It doesn't lead anywhere; it has no other mathematical consequences I can see. And I've never heard of the problem before. How did this make it onto the list?
Taylor Hornby 🛡❤️ retweeted
Bad guys will win if the frontier labs don't let people do work like this.
hashsma.sh has been live for 23 minutes and there are already multiple attempts to challenge the security of SHA3 and BLAKE3.
Taylor Hornby 🛡❤️ retweeted
Announcing hashsma.sh! 𝟘 𝟙 ❒ 🔨
Strengthen cryptography with AI.
Cryptography—both current and post-quantum cryptography—depends on hashes. SHA-256? SHA-3? BLAKE3? Nobody knows if they are secure. We're going to find out!
Come help accelerate scientific research!
HashSmash is an open science-acceleration project in collaboration with @yukonresearch, @eigenlabs, @projecteleven, and @ShieldedLabs.
Taylor Hornby 🛡❤️ retweeted
I would be interested in an actual discussion of AI consciousness that isn’t just assertions, or facile arguments about current models having limited memories. (We don’t treat amnesiacs as lacking consciousness.)
Taylor Hornby 🛡❤️ retweeted
Oblivious HTTP lets a client query a server in an untrackable and unlinkable way (hides the IP and other info)
We’re announcing the closed beta of a self-serve Cloudflare OHTTP Gateway. We’re also renaming our Privacy Gateway to Cloudflare OHTTP Relay to better distinguish the two products. cfl.re/4ARJPKX #BirthdayWeek
Taylor Hornby 🛡❤️ retweeted
I think a few folks missed this paper when it came out. Analysis and Attacks on the Reputation System of Nym
petsymposium.org/popets/2026…
Taylor Hornby 🛡❤️ retweeted
In my 1989 thesis I asked if there was an oracle separating IP from MIP. That was before we knew that MIP=NEXP, though that result doesn't relativize. Bouland, Huang, Natarajan, Shalit, Tal and Astra now answer the original question.
arxiv.org/abs/2609.25680
Taylor Hornby 🛡❤️ retweeted
This is the way. Assume all code has exploitable vulnerabilities, and it’s not possible to patch them before an adversary notices. What now?
Systems designed around this assumption are the most secure, and it’s relevant now more than ever.
