Researchers unveil faster classical attack on RSA signatures

The work narrows RSA’s theoretical safety margin and prompts a fresh look at weak keys and legacy setups.

New academic work describes a classical (non‑quantum) attack that can forge RSA signatures without factoring the underlying key, cutting the computational cost of such attacks by orders of magnitude compared with previous approaches. The technique does not currently endanger mainstream deployments of RSA, but it may apply to some niche or legacy configurations, including 1024‑bit keys that are already considered obsolete. For most users and vendors, this means existing RSA‑based systems remain effectively safe in practice, but the theoretical security margin is smaller than previously believed. For cryptographers and security engineers, the result is a major conceptual development that forces a re‑evaluation of how RSA implementations are designed and which parameter choices remain acceptable over the long term. The work also highlights that serious advances in breaking RSA can still come from classical algorithms, not just future quantum computers, and so implementations should continue migrating away from short keys and deprecated modes of use.