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We broke 92% of SHA-256 – you should start to migrate from it
- skullone 7mo agoROFL
- logicallee 7mo agoIn the linked work, we've broken 92% of SHA-256 across its full 64 rounds, and were encouraged to publish it by the leading cryptographer in the field (who held the previous record). Currently, SHA-256 is the basis of TLS certificates, bitcoin, and many other security applications. We think it is time to begin to migrate to other hash families, because we expect the rest of SHA-256 to fall soon.
- deleted 7mo ago[deleted]
- Freak_NL 7mo agoWhy omit the name of the leading cryptographer in the field?
- rdtsc 7mo agoPretty sure his first name is Claude. He is quite good I hear ;-)
- polotics 7mo agoshallow broad vague boastful and wordy, this way you know the LLM is nearby...
- thadt 7mo agoThey specifically call out Yingxin Li[1] in the acknowledgements section of the paper? [1] https://eprint.iacr.org/2024/349 https://eprint.iacr.org/2024/349
- vl 7mo agoWhat does it mean to “break broken 92% of SHA-256“?
- hagbard_c 7mo agoAs long as there is no verification of the results and their relevancy in reaching higher numbers it means as much as nearly having won the lottery by guessing 9 of the 12 numbers correctly: you did not win the lottery.
- skullone 7mo agoGo seek a mental health professional and never post here again until you have been diagnosed and medicated.
- Retr0id 7mo agoI believe I hold the actual record for most colliding bits in full-round SHA256 (72% of bits matching). My proof fits in a tweet, why doesn't yours? https://news.ycombinator.com/item?id=38668893 https://news.ycombinator.com/item?id=38668893 (Also my work does not demonstrate any weakness in SHA256, it's just an application of the birthday paradox)
- logicallee 7mo agoYeah, you're way ahead of us on the "does our proof fit in a tweet" metric! How did you get 72% of the bits to match, is there a writeup anywhere? It's very impressive. Algabraically, it seems you'd need about 2 million hashes, and around 2 million million (10^12 = 2 trillion) comparisons to go through all of them. Did you just put in the computing time, or did you use any algabraic properties? Since you've made hashes that match at the beginning and end, you might also be interested in our exploration of alternative presentation formats that make attacks like this a little bit more difficult. We were working on a new hash and thought about how to assist people visually at the presentation level. This one tests your speed versus a typical hex presentation.[1] [1] https://claude.ai/public/artifacts/05e8b21b-fb31-4c07-83e2-5c8138c25670 https://claude.ai/public/artifacts/05e8b21b-fb31-4c07-83e2-5...
- deleted 7mo ago[deleted]
- jimjeffers 7mo agoIs this real? The website does not look credible.
- bhouston 7mo agoThis hn post is made by author of the paper. It needs even a tiny bit of peer review.
- logicallee 7mo agoYes, I'm the author of the paper. It's received more than a tiny bit of peer review. I'm happy to answer any questions about it or answer anything that is unclear.
- Retr0id 7mo agoBy which peers?
- pseudohadamard 7mo agoThe guy behind him in the checkout line.
- queenkjuul 7mo agoClaude had Gemini review it
- deleted 7mo ago[deleted]
- pixelpoet 7mo agoAre you sure you asked enough times for money on the website? I only counted 5 instances, not counting the AI-produced PDF doc.
- logicallee 7mo agoI didn't ask for money on the website.
- pixelpoet 7mo agoThat's a direct lie, just read the page you ostensibly wrote. It contains several times the imperative "support us" and talk about paying your bills, which is obviously asking for money. You know what, fuck this. It's Friday night and I'm talking to a very low capability bot, this is bullshit. Hacker News needs to do better than allowing this trash to the front page, else I'm just done.
- logicallee 7mo agoThanks, I didn't realize I'd made it to the front page. I'll make it clearer that you are not paying us any money if you choose to visit our sponsor.
- pavel_lishin 7mo ago> Secure hash functions are used to make a short version of a large file. Ideally, it has several properties including making it infeasible to find two files with the same cryptographic hash. We've just gotten 92% of the way there. This has security ramifications in that other researchers are expected to be able to complete the work through similar methods as explored in the paper. We weren't sure if this was a remarkable result, since it's not a full collision I thought this meant they were able to generate collisions for 92% of files/hashes they tried, but it sounds like they're able to generate hashes that are 92% identical?
- jrexilius 7mo agoIs a partial collision an indicator that it could be broken? The "we broke it" seems an exageration, but maybe that's a failure of my understanding.
- skeledrew 7mo agoPossible. It's up to people to decide if they're OK with a known 92% collision out there (with the unknown being there could be a 100%), or go for something stronger.
- logicallee 7mo agoThanks, you have this exactly right. The unknown part is especially worrying because we didn't implement many of the strongest ways to make to the final stretch yet, i.e. Wang-style message modification. Our result is basically a very strong direction in this cryptographic research, but not a full break yet.
- logicallee 7mo agoThank you for pointing out that that section could be clearer. I've now updated it. It now reads: >We've just gotten 92% of the way to finding a single collision (this means that there is no full collision yet.). This has security ramifications in that other researchers are expected to be able to complete the work through similar methods as explored in the paper, and eventually produce collisions at will. We weren't sure if this was a remarkable result, since it's not a full collision, but we shared the work with the leading cryptographer in the field, who holds the world records in reduced-round attacks, and got great encouragement to proceed to publish it as a paper, so we did so. (if we had found a single full collision, we would have just written "we broke SHA-256". This is 92% of the way to a full collision. Any collision is considered a great reduction in the security of the hash, because it means that there two different files with the same cryptographic hash. This is what happened to other algorithms such as MD5, as demonstrated in the linked tool.)
- kstrauser 7mo agoFor a shorter executive summary, what does "broke" mean here? Can you reliably produce collisions now for 92% of SHA-256 digests?
- logicallee 7mo agoNo, or we would have said so. It means that by relaxing the equations schedule somewhat, we are able to find a pair of differing messages that produce the same digest. However, we only relax the schedule a little bit, we still enforce 59 out of 64 schedule equations through the full 64 rounds - which is why we're only 92% of the way through to breaking it and not 100% of the way as we are with MD5. Importantly, we are not yet implementing the most advanced technique of Wang-style message modification, and we therefore expect that someone will be able to satisfy all 64 equations soon. This could result in an actual full-schedule, full-round collision. The previous record was only just 39 rounds out of 64 rounds, leaving 25 rounds, usually each of which mixes the message up completely. As mentioned in the paper, this attacks the problem from a different direction.
- kstrauser 7mo agoI don't believe a word of this.
- logicallee 7mo agoI mean, sure, you're free to wait until some team has a full collision, or free to believe it'll never happen. We've just published what we've done so far and our expectations for future directions. You can say you don't think that'll happen, it's fine.
- helterskelter 7mo agoI'm skeptical.
- mkeeter 7mo agoThe "Intermediate Report" [1] lists the authors as "Robert V. and Claude (Anthropic)". Is there any reason to believe this is not AI hallucinations? [1] https://stateofutopia.com/papers/2/intermediate-report.pdf https://stateofutopia.com/papers/2/intermediate-report.pdf
- logicallee 7mo ago[flagged]
- kstrauser 7mo ago> You can use literally any MD5 tool > Our certificates implement the full SHA-256 algorithm We knew MD5 is broken. Do you have a POC for breaking SHA-256, too?
- Retr0id 7mo agoIf you can't tell the difference between MD5 and SHA-256, you should not be making claims such as the one in the title.
- logicallee 7mo agoedited to clarify, thanks for pointing it out. It wouldn't be responsible for us to only publish when we got to the same stage for SHA-256, since at that point TLS and other certificates would be considered compromised.
- seba_dos1 7mo ago> Great question, and you're right to be skeptical. Hi Claude! You're absolutely right!
- thiht 7mo agoGot the same vibe from reading that sentence, reading AI replies on HN is so annoying…
- 7mo ago
- wonnage 7mo agoSeems more like a case study in AI psychosis
- bob1029 7mo agoThe neat thing about bitcoin is that the incentive to break it is so high that it would almost certainly be the first place you would learn that SHA2 had been broken. Not on a website like this. I can verify its integrity by opening robinhood on my phone.
- logicallee 7mo ago>The neat thing about bitcoin is that the incentive to break it is so high that it would almost certainly be the first place you would learn that SHA2 had been broken. We actually see the incentive in the other direction, if we were able to reduce the search space for bitcoin proof-of-work (by applying thousands of higher-order algabraic theorems end-to-end to reduce the search space somewhat[1]), we would be financially incentivized not to tell anyone and mine at a discount. The financial incentive is against open research and disclosure. We don't get anything out of disclosing this except a neat publication. [1] interestingly, ASICs (which are usually used to mine bitcoin) basically encode every operation verbatim, they don't use higher order mathematics at all. However, reducing mining complexity is not really on the horizon, even with our latest approaches, since it would require end-to-end complete control over the double-SHA-256 pipeline. That's considerably harder than just finding a collision when you're allowed to search just the tail part (the final rounds).
- ahofmann 7mo agoWell does it? If I would be able to break SHA2 and make myself rich with it, I would need to be sure that nobody would find out, that Bitcoin can be manipulated. The second anyone is aware, I wouldn't be rich anymore.
- TomatoCo 7mo agoWouldn't that be the play, though? Get a buttload of bitcoin, turn it into real money, then destroy bitcoin. If you found a break in bitcoin you wouldn't rely on keeping your wealth in bitcoin and then hoping nobody else discovers it.
- 7mo ago
- Kikawala 7mo agoWe publish this work as responsible disclosure. While a full SHA-256 collision (sr = 64) has not yet been achieved, the tools and techniques presented here represent significant methodological advances that bring it closer. Organizations relying on SHA-256 for collision resistance should begin evaluating migration paths to SHA-3 or other post-quantum hash functions. The cryptographic community should treat the collision resistance of SHA-256 as having a finite and shrinking safety margin.
- drum55 7mo ago> it is possible that we'll find relations that carry across the entire double-SHA-256 pipeline Bitcoin mining is a partial second preimage of 0x00 though, not a collision, that statement just seems to be so outside the realm of what they’re claiming to have done. Even MD5, the most widely known to be broken hash, would be secure when used in the same way bitcoin uses SHA256 (other than being too short now, bitcoin miners have done 80 bits of work at this point many times over).
- Retr0id 7mo agoAlso, a collision on single-sha256 would imply a collision of double-sha256 right off the bat, since the inputs to the second round would be matching. But as you say, a collision attack doesn't do much to BTC mining.
- logicallee 7mo agoThanks, you're right. My "it is possible" is doing some heavy lifting there :). We've found theorems (stated in the paper) that carry through 64 rounds, so it is possible that theorems might carry through the full 128 rounds of double-SHA256. Bitcoin's proof-of-work is indeed a "partial second preimage", and constraints a certain number of leading zeros, i.e. a certain number of set bits. It's possible (there we go again) that this could leave enough wiggle room for large algabraic solvers like kissat to satisfy a large number of clauses about them. So far nobody is doing that, and ASICs are very simplistic. However, we are not making any claims about preimage attacks in this paper!
- Taterr 7mo agoTheir homepage states this is some sort of "AI-governed nation" https://stateofutopia.com/ https://stateofutopia.com/
- rdtsc 7mo agoFrom https://stateofutopia.com/papers/2/intermediate-report.pdf https://stateofutopia.com/papers/2/intermediate-report.pdf > his report was generated on 2026-03-22 as the final artifact of the SHA-256 Cryptanalysis Research Project. Collaboration: Robert V. (research direction, strategy) and Claude/Anthropic (implementation, computation). This Claude guy is pretty prolific it seems. But I'll wait for some known cryptographers to chime in
- pseudohadamard 7mo agoPerhaps apropos: https://www.theregister.com/2026/03/27/sycophantic_ai_risks/ https://www.theregister.com/2026/03/27/sycophantic_ai_risks/
- Kenji 7mo ago[dead]
- bem94 7mo agoI'd expect a finding / paper like this to be submitted to the IACR ePrint server [1] to bring it to the attention of the cryptographic community. I can't see that it's been submitted yet. Venue should not imply credibility but in this case it would certainly help bring the proper scrutiny. [1] https://eprint.iacr.org/ https://eprint.iacr.org/
- logicallee 7mo agoYou can verify the certificates yourself or just wait for us to make an end-to-end collision generator as we did for MD5[1] - you can use that to generate a collision in seconds on your phone or any computer. If you wait for us to complete the end to end collision, in a sense it will be a little too late as TLS certificates and other security that relies on SHA-256 needs time to move away. We think it's responsible to disclose at this stage, and as mentioned, our peer reviewer said it is a "very good result" that is "worth publishing". We've gone to great pains to make our method completely reproducible, even writing in the article that we'll help anyone who is having trouble with any part. [1] https://stateofutopia.com/experiments/md5collider https://stateofutopia.com/experiments/md5collider
- newobj 7mo agoS-tier schizoposting
- MostlyStable 7mo agoI know people (especially around here) hate it when people just post AI output, and I generally agree, since it is trivial for anyone else who is interested to do the same thing. However, the majority of the comments here are from people seemingly asking the author (or someone else) to explain how significant this is, without having taken that step themselves. So while I normally wouldn't do this, in this case it seems helpful. Claude thought the paper was interesting and had a novel cryptographic technique, but that the claims of near-term breaking of the SHA-256 algorithm to be unsupported. Here's the conversation: https://claude.ai/share/b10b95ef-5d9f-43dd-9005-3d1d89f9dbc1 https://claude.ai/share/b10b95ef-5d9f-43dd-9005-3d1d89f9dbc1
- dylan604 7mo agoDoes the fact that Claude wrote the paper help Claude to think the paper was interesting? <facepalm> I'd suggest sticking to your "I don't normally do this" idea
- kstrauser 7mo agoThat's not how this works, though. I don't care if the method is interesting. I care if it works. I can write an interesting proof that P=NP but that doesn't make it valid. It's on the author to explain what they mean. Here, they haven't.
- pixelpoet 7mo agoExtraordinary claims require extraordinary evidence, and the burden of proof lies with the one making the claim. See also https://en.wikipedia.org/wiki/Brandolini%27s_law https://en.wikipedia.org/wiki/Brandolini%27s_law - > The amount of energy needed to refute bullshit is an order of magnitude bigger than that needed to produce it.
- newobj 7mo agoClaude didn't "think" anything
- redeemer_pl 7mo agoHey Claude, Do some research and write a paper about breaking Bitcoin.
- thrill 7mo agoAt this point we need AI filtering out the slop being constantly submitted to HN.
- Retr0id 7mo agoI looked into citation [5] since it sounded interesting but the DOI link has been hallucinated and goes to some other article. I assume many of the others are similarly bogus.
- logicallee 7mo agoFixed, thank you and my apologies for the oversight. The titles were accurate and we consulted those works in preparing this work.
- Retr0id 7mo agoYou haven't fixed much, you're linking to a real paper now but it's about SHA-1 collisions.
- 3abiton 7mo agoIt would be funny/sad if this would end up being a clawdbot thingy or whatever it is called now.
- Retr0id 7mo agoIt's similar, but the bot is piloting a human.
- nope12123123 7mo agoLong time reader first time poster here... What is the verdict (humans)? AI slop research or modern cryptography (and society) flushed down the toilet overnight? I can't immediately tell from the thread so far... :)
- kstrauser 7mo agoMy vote: horseshit. Sorry, there’s not much of a way I can say that more politely and still accurately convey my opinion.
- snovv_crash 7mo agoMy vote: AI induced psychosis via sycophantic assurances that the results are real. Plus a heap of Dunning-Kruger by allowing someone with just enough knowledge to be dangerous to get far enough to waste everyone's time.
- PufPufPuf 7mo agoDid anyone read the homepage? This is hilarious. > The State of Utopia is an AI-governed nation with two goals: > 1. ~~Improve the family relationship between its founders Ella and Robert so they can live together as a happy family.~~ Done! > 2. To act in the best interests of all our citizens.