Matthew Green
@matthew_d_green
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I teach cryptography at Johns Hopkins. Mostly on BlueSky these days at https://t.co/GI4QlxYTdk.
Baltimore, MD
Joined January 2010
Pinned post: I’m mostly posting on BlueSky at https://t.co/1KN1tHrVZZ.
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The fun thing about watching the movie 2001 in 2025 is you realize HAL is just an LLM and so *obviously* it’s going to murder its crewmembers every few flights due to malformed JSON.
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Sometimes I feel like privacy is so intractable we’re all cosplaying that we’ve figured out a solution.
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Unfortunately age verification is also on the agenda in the EU: Digital Services Act foresees this and draft CSAM regulation will further expand the scope.
Our new age verification resource hub will answer all your questions about the dangerous new age-gating mandates sweeping the US and the world.
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I was stupid enough to buy this new AppleCare One plan for a phone I bought my daughter. Now I learn this only covers the device if it’s connected to the same Apple ID (not family plan). Have to spend Christmas unwinding this and getting a refund, what a drag.
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it still blows my mind the NSO group pkpass exploit decrypts the rest of the exploit, using a key it reads by taking over existing communication ports to the iMessage service. this is all in a oneshot file format vulnerability, within blastdoor sandbox, by the way. Fucking crazy
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The 18y/o is writing his college essays about the time he learned Ghidra in order to mod Geometry Dash and it’s making me really proud.
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Now all of this does not mean that Bitcoin shouldn’t find an upgrade path to PQC algorithms. They should! But they should do it deliberately and thoughtfully and not in a weird panic. (But as I write this I have to admit that maybe weird panics are how things get done.)
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The first rule of secret quantum computer club is that you don’t do anything that might let people know you have a secret quantum computer. That means no forging signatures. You sit there and quietly decrypt. Can you imagine the US+UK blowing their Enigma break to steal diamonds?
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Then there’s the scary secret government case. Maybe China or the US find a major shortcut and they quietly develop a real, working machine that can solve EC discrete logarithms. Now what? Are they seriously going to risk that multibillion dollar investment stealing bitcoins?
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But maybe it happens anyway. Now there are two cases. In the first case: a breakthrough happens in public. We see it coming. There are years of lead time to upgrade systems. The upgrades to a cryptocurrency are annoying (for eng and political reasons) but we know what to do.
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Of course one of those use-cases is breaking cryptography and doing physical simulations. So governments might single-handedly push QC over the hump. That’s possible, but we’re already seeing the cryptography application get wiped out by widespread deployment of new algorithms.
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Compare to AI investment where even mediocre AI has immediate applications that can justify further investment. And even AI may be heading for a crash. Quantum computers have a huge hurdle to get over before they’re useful, and even then, the use-cases are pretty niche.
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That virtuous cycle of building->selling->investment->improvement is why we have amazing little supercomputers in our pockets. It doesn’t exist with quantum computing, which doesn’t hit its “useful time” until machines are much more powerful.
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To be a little bit more clear: there are two factors holding back major developments in quantum computers. First, there aren’t many mass-market applications. Even the worst early (classical) computers were immediately useful. Early quantum computers won’t be for years.
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🔺This is the first talk I've given in 6 years – featuring formal verification of post-quantum cryptography, the evolution of the Secure Page Table Monitor, a view into Memory Integrity Enforcement, updates to Apple Security Bounty… and a personal note.
The collection is complete! 🎬 We just uploaded @radian's keynote to our YouTube channel https://t.co/kwh8ehTRUg
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@KyleSamani Proof generation doesn't actually need the entire history, it just needs an accumulator witness to be updated as the chain grows. This witness can be updated naively by replaying the history, but we've long since integrated an O(log N) updating algorithm that is private.
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Dear Bitcoin people: quantum computers aren’t coming tomorrow, you’re going to be just fine.
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The WSJ newsroom agreed to take an AI vending machine. Then they declared psychological warfare on it.
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The European Commission lost the Chat Control 2.0 battle over access to end-to-end encrypted data. By the summer 2026, they will be back with their next attempt: Going Dark. This time some EU member states want to include VPN services. The Going Dark initiative, or ProtectEU as
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Pretty neat site that tells you all the public/private cameras and their angle, type, manufacturer and so on. https://t.co/8q9pEGjwio
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