Mythos attack on 3rd-round PQC algorithm candidate puts it out of commission

A quantum-resistant cryptography algorithm that was under consideration as an official US standard has been taken out of the running after an Anthropic security model helped find a flaw that rendered it broken. The algorithm is known as HAWK. It’s a digital signature scheme designed to withstand future attacks from quantum computers. HAWK had survived two rounds of testing by NIST (the National Institute of Standards and Technology) for evaluating the security of PQC (post-quantum cryptographic) algorithms through widespread testing. HAWK was in a third round of testing designed to catch precisely the kinds of flaws Mythos helped uncover. Following Anthropic’s Monday announcement of the results, the developer of HAWK said Tuesday he was withdrawing it. Even before the development, Anthropic was hailing the results of the two cryptographic problems it threw at its Mythos AI security model. The model found weaknesses in the mathematical problems underpinning HAWK and, separately, the widely used AES cipher. Despite the withdrawing of HAWK, it’s hard to know how much of the company’s reporting is marketing hype, but the findings are still worth paying attention to because they could signal important advances in breaking cryptography that’s crucial to privacy and security. Before digging into the results, a few caveats. First, the outcomes are incremental. They don’t break any of the cryptosystems anyone relies on today. Instead, they reveal methods for moderately reducing the work that would be required to defeat the systems. Second, the cryptosystems tested were weakened versions of the ones defined in their formal specifications. Such “challenge instances” are provided by the specification authors for use in adversarial peer review. It’s standard to use the weakened versions in testing, but the real ones are considerably more robust in production settings. As Bruce Schneier said when reviewing another incremental improvement on the attacks on AES: And as he often says Edit: reorder paragraphs and trim original quote.