Anthropic announced that its unreleased AI model, Claude Mythos, discovered new attacks on advanced cryptographic algorithms. Its first target was HAWK, a digital signature system competing to become a US federal standard. The system is the last remaining lattice-based candidate in the third round of NIST’s post-quantum signature competition.
During testing, Claude uncovered a hidden symmetry in HAWK’s mathematics that slashes the cost of recovering the secret key from 2^64 operations down to 2^38 operations. This vulnerability makes the key 67 million times easier for an attacker to break. Fixing it requires doubling HAWK’s key size, wiping out much of the scheme’s edge as a post-quantum cryptography candidate.
Breaking AES and a LEA Record
The AI model also targeted AES by producing a “Möbius Bridge” technique on a 7-round version, eliminating one of nine key bytes an attacker previously had to guess. A third attack targeted the LEA algorithm, a South Korean national standard and ISO lightweight encryption standard for mobile phones and IoT devices. Claude broke 13 rounds of LEA in under an hour on a desktop computer, surpassing the previous record that required 2^98 plaintext pairs.
To benchmark performance, Anthropic built CryptanalysisBench, comprising 191 cipher-breaking tasks. The Mythos 5 variant solved 85.7% of solvable tasks on this testbed. Anthropic stated that the majority of mathematical findings in their paper were AI-assisted, with human authors primarily directing, organizing, and verifying the machine’s output. A post by WatcherGuru about the breakthrough quickly drew industry attention, amassing 3132 likes on X.
What Does This Mean for Block Space Costs?
For blockchain networks, cryptographic signature sizes directly dictate blockspace consumption, and blockspace capacity determines transaction fees. On-chain networks seeking quantum-resistant replacements evaluate new options largely based on bytes per signature. If an algorithm like HAWK is forced to double its key size to patch a vulnerability, implementation and transaction costs across the network will surge drastically.
Where Bitcoin Holders Stand
Amid AI advances against high-level algorithms, Bitcoin still operates on the pre-quantum ECDSA scheme, meaning user funds remain safe for now. However, the erosion of HAWK’s advantages offers a clear takeaway for the crypto community: finding future algorithms is not just about shoring up security walls, but ensuring the cryptographic design remains lightweight and cost-effective when networks eventually upgrade.
Reported by Decrypt.
Disclaimer: This article is for informational and educational purposes only, not financial advice. Cryptocurrency assets are highly volatile and carry significant risk. Always do your own research (DYOR) and never invest more than you can afford to lose.
