Researcher Stephen A. Weis successfully factored the 896-bit RSA-896 semiprime on September 19, 2026, using the Claude AI model from Anthropic. This achievement set a new public record, surpassing the previous 862-bit mark established just 16 days earlier.
On September 3, 2026, Eric Lu of Cognition factored the 862-bit RSA-260 number using the company's Devin AI agents. This process required approximately 4,900 GPU-days of computation, with costs estimated at $400,000.
Both researchers utilized the general number field sieve (GNFS), a classical algorithm used since the 1990s, rather than quantum computing. AI tools were employed to optimize and accelerate the classical approach, reducing tasks that previously took months.
While RSA-896 has been factored, the industry standard remains RSA-2048. Because each additional bit roughly doubles the difficulty of factoring, 2048-bit encryption remains significantly more secure than the numbers broken in these recent experiments.
Experts advise organizations to audit systems using RSA keys below 2048 bits, particularly legacy hardware and older TLS configurations that may still rely on 1024-bit keys. The recent records highlight the need to move away from these insufficient standards.
