CS Prof. Security and applied cryptography. Some highlights: Zerocash (zcash, et al. ), Zexe (Aleo, Aztec, etc ), zk-creds/zk-promises(...)

Washington DC/ UMD
Joined April 2012
“I ran <best internal model> for N trillion tokens at <frontier lab> and it couldn’t even dent <fundamental assumption>” should automatically get Best Paper at CRYPTO/Eurocrypt.
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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.
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In case people think I am advocating for not being cautious, or thinking that AI won't be an issue for any cryptography, that's not the case. Let me word what I think would be a balanced approach regarding AI and crypto. 1/n
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Ian Miers retweeted
To be clear: I don’t know if AI breaks hash functions or ECDSA, or neither. Nor does anyone else, especially the people posting overconfident takes. We'd need evidence and there wasn't any. There’s a case to be made that hashes are historically what’s been broken. There’s also a case to be made for modest improvements in, e.g., factoring algorithms, and key sizes getting bigger. And there’s a case to be made for catastrophic breaks. A bolt from the blue, so to speak. What you shouldn’t say is “oh, hash functions are safer because they have less structure.” That gives a verifiably inaccurate impression of past history. Hence my deliberate hyperbole stating the opposite.
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Having long been aware of those tech bros who read my work as utopian porn, where they’ve taken that doesn’t exactly surprise me.
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I’ve had a few people write to ask me to follow up on a (reply!) tweet I wrote that’s gotten a lot of retweets. I considered deleting it just to avoid the headache, but I think that would make people more paranoid. So let me share my thoughts.
Replying to @kmad @matthew_pines
I think we might lose public key cryptography.
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PSA: Practical cryptographic hash functions have a lot of structure, less mathematics backing up their security, and are often assumed to satisfy properties they do not achieve (in particular, being random oracles).
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AI is very likely to help cryptanalysis, in some form, but I see no technical evidence to justify the claim that public-key assumptions are more at risk than symmetric constructions.
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Ian Miers retweeted
Hi. If elliptic curves are broken so that any exposed public key leads to compromise and it's by a financially-motivated hacker who’s top priority is to steal crypto, the entire fucking world is going to zero. Having your magic internet coins in bunker mode is not going to help you. It would mean some random ass fucking cyber criminals > every developed nation state and private corporation in the world.
Hi. If elliptic curves are broken so that any exposed public key leads to compromise, and it's not by white hat hackers who save everyone's assets first, your coins are going to zero. Having them in bunker mode is not going to help you. They are still worth zero.
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Ian Miers retweeted
Signal's automatic key verification uses the IETF keytrans design. Very roughly it's the prefix tree construction: hash of (username, version) gives the path in the Merkle tree to the leaf with the entry. You check both the current entry and that there isn't a newer entry for version+1. Each new root of this tree is stored in an append-only log. Auditors are responsible for checking that updates to the log are correct. Alice only needs to periodically check that the current entry for her public key is hers. Nb: technically it's not the hash, it's a vrf, using a server secret key to avoid anyone enumerating usernames. datatracker.ietf.org/doc/dra…
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NEW: A Federal judge just ruled that a warrantless Flock/ALPR search violated a woman's 4th Amendment rights! "Why is it the government's business where everyone goes all the time?" "Freedom from persistent, dragnet-style surveillance while in public is not a foreign concept in our society, and it is a reasonable expectation that society already accepts" Judge Sara Hill (N.D. Oklahoma) notes other courts, including in Oklahoma, ruled the other way on Flock searches. She argues that a decision from 1983 shouldn't govern 2026 networks of what she calls "indiscriminate mass surveillance." "This Court is now faced with technology that appears to be approaching the dragnet type law enforcement practice Mr. Knotts warned of." Setting up for an interesting fight in circuit court if the government appeals. Story by @jason_koebler 404media.co/federal-judge-ru… Ruling: storage.courtlistener.com/re…
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“Who’s a good boy?!” Hackers just dumped the contents of a Flock camera. They found: 🔴Software explicitly detecting people, not just plates 🔴1.6 million images logged in 21 days 🔴Key to decrypt files stored on the device itself. Finds directly contradict Flock, which claims someone with physical access can't access images. Making it worse,@GainSec warned about the physical access issue more than a year ago & Flock downplayed it. And yeah, the Flock camera logged “Who’s a good boy?!” about every 2 minutes, all while plagued with errors, crashes & reboots. By @dmehro & @josephfcox wired.com/story/hackers-floc…
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Ian Miers retweeted
“KYC” isn't a defined reg term. It's people combining parts of CIP, CDD, EDD, OFAC & recordkeeping rules w/ different req’s. Some allow reliance, non-documentary verification, or risk-based procedures that don't inherently require full clear-text PII, let alone direct escrow.
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So my concern when I look at a Meta (or Google, or even an Apple) is not about how they’ll do inference privately, that’s a commodity. The question is how they’ll keep themselves from accessing that valuable distilled data once it’s right there.
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When it comes to Internet privacy, there’s surprisingly little daylight between the UK and China.
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This is a good post on the impact of surveillance in Iran: myprivacy.blog/the-digital-i… It's worth reading. IMO one mistake that freedom advocates often make is that we talk about privacy violation and surveillance as "dystopian", using the word as a semantic stop sign: we know it means "bad", we nod along, and don't really go further to clarify why it's bad. I worry that this approach is long-run unhealthy: when we criticize various companies and countries for being "dystopian" and stop there, then to someone who's not already in the same memeplex, it sounds like we're basically criticizing companies and countries for not complying with our culture's aesthetic preferences. Which is ... duh, companies and countries are *supposed* to not comply with each other's aesthetic preferences, that's the whole point of the "pluralism" thing. What the above article makes clear so well is that "dystopian" surveillance is not bad because it's "dystopian", it's bad because it makes a concrete property of the world worse: the power balance between individual and state. Surveillance enables an outcome where basically everyone other than police and security forces has no opportunity whatsoever to challenge the political status quo without being punished. This means an outcome where a political regime can remain in power forever, without satisfying more than a very small coalition of people who have the eyes and the guns (now drones). The Dictator's Handbook talks about "large coalition" and "small coalition" governments; large coalition governments are the ones that are more pro-human, because they, well, have to keep a large coalition happy. Small coalition ones are the really nasty ones. Here is the near-term dark outcome of dictatorship + automated warfare + surveillance: a regime can literally survive with a coalition of size 1, because an army of all-seeing eyes and robots can defeat the entire populace in battle if needed. In Iran, we see what *just* dictatorship with surveillance can do, once you add automated police, you get to the unholy trifecta. I don't know of a good solution to this. Privacy technology, as well as more work on censorship-resistant internet (I think we should strive for at least basic-quality internet, eg. 1 Mbps, being a global human right outside the domain of nation-state sovereignty), can help somewhat to reduce the possibility of total government control. But what else? --- BTW one implicit frame in the article I take some issue with is framing Iran + Russia + China as the unique antagonists (both in surveillance they do internally, and in the technology they export to other countries). They do a lot of dystopian shit of both types. However, Israeli and US tech companies, and undoubtedly tech companies from other Western nations, also do a lot of dystopian shit. Perhaps one key difference between the surveillance described above, and the Western type, is: * The surveillance in the above article is about exercising *great control over a medium area*: you can see everything, but it requires active participation of the government of the territory being surveilled. * The Israeli / US / Western flavor is about exercising *medium control over a great area*: there are more limits to how much they can do, but their surveillance is global: they know what people are doing even in countries and territories they have no presence in. The distinction is not absolute: Israeli surveillance backstops a lot of its human rights abuse in Palestine, US surveillance reinforces ICE abuses (see the recent article about Homeland Security demanding social media firms reveal names of anti-ICE protesters), etc, and "transnational repression" is done by anti-Western countries. But *on average*, the above seems to be the pattern. The two are differently scary. The former for the reasons I described above. The latter because it allows global projection of power: a politician or civil servant in one country now has to worry about being blackmailed, droned or otherwise attacked from other countries. The USA has shown willingness to go after individual EU officials, ICC officials (see recent articles on both), and others. Ultimately, I suspect that even democratic governments will want more privacy to protect themselves, and we will have to have deep conversations about what "democratic accountability" means: how can a civil servant be accountable to the people, but not accountable to foreign spooks? My high-level frame is: privacy generally helps whoever is weaker. "Weaker" does not mean "moral": sometimes the weaker side is criminal. But in the 21st century, we are at serious risk of stronger factions using modern technologies to establish unbreakable lock-in to power. And so on average, reducing the gradient of power, giving the weak a fighting chance, is something that the world desperately needs.
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NEW @gwartygwart pod w/ @secparam: Zcash resurgence, Privacy, & Quantum "Privacy is not just about payments. It's accountability, ways to express yourself safely, show qualifications without completely doxing yourself." Brought to you by @ellipsis_labs
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It's getting to where the first thing I do when I read a piece critical of AI --- lots to be critical of! could destroy the economy the way equity tranches of mezzanine CDOs did in 2007! --- is scan for "water". If they're freaking out about water, I'm done.
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One of the most interesting recent privacy developments is the deployment of big two-hop IP blinding VPNs by companies like Apple and Google. These systems are designed to ensure that even those companies can’t link web requests to IP addresses.
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The Tachyon concept/architecture is such an elegant solution to nullifier scalability: Evolve nullifiers over epochs Reveal/store nullifiers for the current epoch only Prove unspent in a past epoch Outsource proving to oblivious service via recursive proofs Infinity unlocked
New work with @ebfull on scaling Zcash and Zexe-derived protocols like Aleo and Aztec. zkSNARKs are now a (fantastic) commodity. They were always just one piece of the puzzle: building a secure protocol architecture for "shielded state" manipulation. eprint.iacr.org/2025/2031
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