CS Prof. Security and applied cryptography. Some highlights: Zerocash (zcash, et al. ), Zexe (Aleo, Aztec, etc ), zk-creds/zk-promises(...)
Washington DC/ UMD
Based in United States
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Something is a little surprising with the papers results. We'd expert diversion to be large amounts by corrupt insiders, which seems unlikely to show up as a spike in transaction volume a month later.
And apparently they don't have geolocation data for transactions, they used web traffic by country as a proxy.
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Again, I want to emphasize, the socio-political constraints in Bitcoin are not invented by the authors of Shielded Bitcoin, and they are what lead to the complex design and its downsides. It looks like it’s the best you can do under the circumstances if you want to keep Bitcoin as is. It’s impressive in that sense.
I'd say it’s the idea I would have come up with too given these (absurd) constraints, but the truth is I'd have given up and found some folks to make their own blockchain.
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Why does adding private payments to Bitcoin seemingly require witness encryption, the cryptographic equivalent of a jetpack? Why is that awesome, impressive, and a bad idea? And how do you make a cryptocurrency like Bitcoin or Zcash private in the first place?
To answer that, we need to cover 1) why Bitcoin is public, 2) how you fix that, 3) the socio-political complications using that solution in Bitcoin, and 4) the cryptographic jetpack workaround.
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My grad students and I are looking at zk proofs for human-generated content, and we keep wondering how often folks nominally want authentic content but mainly want to believe things they like For example:
a dude with a $900/year AMEX card asking if he's the asshole for not letting his GF use their free dining credit on a steak.
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In a few months we will have: "Muse: Hey girl, I know you still think about him, want to see where he's been?"
And guides like we got with Venmo:
Anthropic marketing: We built a god only we can control and gave it a “wet lab”
Muse marketing: Heyy girl I know you have dozens of unpaid parking tickets. Let’s get that cleaned up
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So what originally got me thinking of DSA as mangled Schnorr (beyond the obvious patent avoidance issue), was a version of ECDSA someone put up at RWC 2016.
Its a little hard to read, so I just asked Gemini for a cleanup version with Schnorr and Elgamal next to it.
Its not a perfect fit. But its kinda interesting.
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4/ Paper: eprint.iacr.org/2022/878
Talk: piped.video/watch?v=TKudtC48…
A bunch of folks have built faster proofs over more IDs, but many miss the bigger idea: Proofs of passports are a simple input; identity is programmable, composable, and needs more than what’s in your passport.
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Dissidents often use cryptocurrency without understanding the threats. Crypto is Twitter for your bank account. And not all privacy solutions are equal. I cover a few approaches in "Satoshi Has No Clothes." Ironically, the flooding attacks is too basic... piped.video/watch?v=9s3EbSKD…"
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Jokes aside: IACR uses Helios for voting, which is an awesome project that lets you run a low-stakes election with integrity and anonymity. Votes are encrypted and added together. Then three parties together decrypt the sum. If one drops out, then, by design, it’s over.
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Thanks, so assuming no cost breakthroughs(dubious) and no error correcting code improvements (dubious), we need 10^5-6 qbits at 10^12-13 dollars per qbit, so 10^17-19 dollars. So only 100 million billion to 10 billion billion.
Financed, allegedly, on "Bitcoin recovery"
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Quick refresher: Nullifiers prevent double-spending/replays/forks in anonymous payment and smart contract schemes.
A ZK proof shows you have money, but not that you haven't already spent it. This is literally why Satoshi didn't know how to use ZK in Bitcoin.
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This is a really bad take. Those privacy protocols have major problems.
And i'm not saying that to shill Zcash, because you can and should take the techniques and use them on your own chain. There can be multiple chains with privacy.
piped.video/watch?v=9s3EbSKD…
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As always you guys have excellent summaries:
TLDR: Nope, its the same small anonymity/decoy style schemes we know don't work.
Satoshi still has no clothes.
reports.zksecurity.xyz/repor…
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So the first copy of cryptonote (titled 2.0) on archive.org (web.archive.org/web/20140620…) gives this somewhat interesting PDF metadata. (click the menu in the right corner->document properties)
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Some "AI" on my phone is reading inbound Signal messages. I left predictive typing on, trading a little of my privacy for convenience. Yet something is giving responses using what others wrote in chats with disappearing messages, persisting or sharing who knows where. Bad default
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The 2010s internet: Let's mock dissertation-length arguments about weird-ass fanfic tags.
The 2025 internet: 'dubcon' is an ancillary part of the financial privacy discourse.
The past was a better place.
bsky.app/profile/acvalens.ne…
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We've crossed a threshold. A paid subscription used to be the ultimate proof of humanity online, now its not enough to allow a single link click inside the NYT cooking app. The next few years are going to be an interesting race to extract more and more invasive proofs of humanity
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Just to clarify, despite what you said on the thread earlier, you all do not run a proving service? Or is the proving service not for zk proofs for payments?
prover is part of payy network -- we run them in house currently (docs.payy.network/payy-netwo…)
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So the original idea was there
1) in the proxy model (which assumes the proxy is not MITMd)
2) without zk proofs, instead relying on a dispute process.
So now we move to:
1) when did ZK/MPC come in
2) When did the application become more general
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Its the weekend and I have grant proposals to write, but need a distraction. So here's a crypto meme crudely edited to accurately summarizes the state of privacy techniques on blockchains.
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Classic Google: an A/B test (a rare overt one)
Classic Google AI: it doesn't actually work (you can't submit)
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I've always explained Bitcoin's lack of privacy as 'It's Twitter for your bank account.' Everything you do is broadcast publicly—it's the opposite of private.
Now it's come full circle, with Elon describing Twitter's (sorry, X's) encrypted DMs as 'Bitcoin-style encryption.
All new XChat is rolling out with encryption, vanishing messages and the ability to send any kind of file. Also, audio/video calling.
This is built on Rust with (Bitcoin style) encryption, whole new architecture.
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Incidentally, if your Signal is now flooded with work chats, you can organize chats into folders
Settings->Chats->Chat Folders. Looks like its Android only for now.
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Ok, so on a technical level what comes next:
1) faster zk proofs.
2) zk-creds that combine a bunch of identity documents, and also have their own data in them. This requires a bit more than just a zk-proof you have a passport. piped.video/watch?v=TKudtC48…
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@mer__edith points out the real story with Apple disabling encrypted backup (and therefore effectively iMessage encryption) in the UK.
The UK is demanding a global backdoor for all data, including Americans. Apple is resisting as best they can.
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The zkSNARK revolution in crypto wouldn’t exist without academic grants for:
1) the paper we built Zcash from
2) literal decades of zk research
It's sad when folks like Zooko, whose main lifetime achievement is commercializing NSF-funded research, are crapping on it for clout.
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Remember, its only cryptology if it comes from the Aés region of France, otherwise its just sparkling garbled bits.
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Question someone asked:
Why the increase in Bitcoin nodes running over Tor?
Is this organic growth, some default, an odd measurement artifact?
Whats the motivation?
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Zama is awesome, built by good people. But this thread reminds me of a question I keep asking about it ....
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Has anyone seen good tools for using LLMs to revise text? I.e., that give you diffs/tracks changes?
Writeful has good tools, but its LLM is bad.
Amusingly, I've seen tools using ChatGPT. But, they use ChatGPT to generate the diffs!!!!!!
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Correction, I got it wrong. It wasn't a fax machine format that was exploited. JBIG2 was used in high end office copiers scanners . E.g., A Xerox WorkCentre 7500 series multifunction printer, which used JBIG2.
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Some things never change ....
Literally, this is still up on WikiLeaks's donation page as of tonight.
Amazing to me that within a few minutes of a newsworthy event (someone donating bitcoin to Assange) folks could located the transaction and sender address. And I don’t mean amazing in a good way.
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The Pinocchio authors, who had the first zkSNARK library, worked at Microsoft and IBM at the time. Much as IBM might now desperately want some blockchain legitimacy, I cannot see the licensing working. If Matt had checked his email, we would have gotten Zerocash, but not zcash
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Zerocoin had two problems: 1) it was a mix, not payments (if this sounds like Tornado cash, it because it is) . 2) the proofs were huge and slow to verify. It was clear we had the right idea, but needed to design new protocols with better cryptographic primitives....
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Great talk by citizen lab's @billmarczak on mercenary spyware circumventing encrypted chat. Stark contrast between Apple's much hyped security against hypothetical quantum computers, and real iMessage exploits that pretend to be a fax machine message. #realworldcrypto
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Should you submit your paper to the Privacy Enhancing Technology Symposium, an XKCD style flowchart:
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To whoever is writing a Usenix Security paper attacking the IACR's voting scheme, good luck with your submission in 58 hours.
Also, stop spamming me.
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ALT FHE is just MPC with 90% of the compute on an untrusted server. Same applications, same trust reqs CHANGE MY MIND
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