Researchers Crack 1,024-Bit RSA Encryption Without Factoring, Undermining Global Security Standards

UC San Diego and Inria Nancy researchers developed a signature forgery attack that breaks 1,024-bit RSA encryption without factoring the underlying primes. The method required 1,380 CPU core-years over a five-month period on an academic cluster, drastically undercutting previous estimates of 500,000 to 1 million CPU core-years needed to factor the key. The technique relies on a 2007 variant of the number field sieve algorithm, though it remains ineffective against RSA implementations using PKCS#1 v1.5 or PSS padding. Ars Technica notes the results push 2,048-bit and 4,096-bit keys to unacceptably low security levels based on standards from the National Security Agency, NIST, and the European Union. "If this result holds up under peer review, it would indeed be a conceptual break-through. RSA is as difficult to break as it is to factor large integers, at least so we thought." — Karsten Nohl