RSA-896 factored with AI assistance, pushing the public record to 896 bits

Cryptographers have been chipping away at RSA factoring records for decades, but the pace just got uncomfortably fast. On September 19, 2026, researcher Stephen A. Weis factored RSA-896, a 270-decimal-digit semiprime, with help from Anthropic’s Claude AI model. The achievement moved the public factoring record from 862 bits to 896 bits in 16 days. To put that timeline in perspective: the previous record had been set on September 3, 2026, by Eric Lu of Cognition, who used the company’s Devin AI agents to factor the 862-bit RSA-260 number. Two researchers, two different AI systems, two records in just over two weeks. What actually happened here Both breakthroughs relied on the general number field sieve, or GNFS, the classical algorithm that has dominated large-number factoring since the early 1990s. No quantum computing was involved. The AI assistance accelerated and optimized the classical approach rather than replacing it with something exotic. Lu’s RSA-260 factoring consumed roughly 4,900 GPU-days at an estimated compute cost of $400,000. Weis’s RSA-896 effort has not had its compute cost published, but the 16-day gap between the two records suggests the AI-assisted optimization ...