Bitcoin's quantum plan assumes some algorithms break. AI just weakened one in 60 hours

TechBitcoin's quantum plan assumes some algorithms break. AI just weakened one in 60 hoursThe HAWK system isn't deployed anywhere, and Bitcoin doesn't use it. But is sitting in the same quantum race that Bitcoin developers are scrambling to finish.By Shaurya Malwa Jul 30, 2026, 4:16 a.m. 2 min readMake preferred on ShareShare this articleCopy linkX iconX (Twitter)LinkedInFacebookEmailMake preferred on SummaryShowAnthropic’s Claude Mythos Preview model uncovered a flaw in the proposed HAWK digital-signature scheme that effectively halves its smallest key strength, undermining one of the candidates to replace current web and banking signatures in a post-quantum world.The AI-driven attack, which cost about 60 hours and $100,000 in computing, slashed the work needed to break HAWK’s smallest parameter set from roughly 2^64 to 2^38 operations, while rendering larger, compensating key sizes far less attractive.Although today’s bitcoin and ether signatures are unaffected, the results reinforce warnings that classical cryptanalytic attacks are rapidly improving, just as bitcoin and other networks debate how and when to migrate to quantum-resistant cryptography.AI heavyweight Anthropic said earlier this week that its Claude Mythos Preview model had discovered an attack that halves the effective key strength of HAWK, a proposed replacement for the digital signatures that protect online banking and web payments.The work took about 60 hours and roughly $100,000 in computing costs, against an algorithm that had survived two years and two rounds of expert human review.Digital signature schemes such as HAWK prove that a message or data set came from whoever holds a particular digital key that points to that exact message. Bitcoin uses one every time a coin moves, and so does every website showing a padlock in the browser.The versions in use today are expected to fail to quantum computers, and HAWK is one of the candidates under review to replace them. It has not been publicly de…

Bitcoin's quantum plan assumes some algorithms break. AI just weakened one in 60 hours

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