Signature Forgery

Researchers Devise Signature-Forgery Attack That Weakens RSA Without Factoring Keys

A team including UC San Diego professor Nadia Heninger published research describing a new classical-computing attack that forges RSA signatures without factoring the underlying keys. The method reportedly cracked deprecated 1024-bit RSA keys in a few months using an academic CPU cluster, far less effort than factoring would require, and it also degrades the theoretical security of 2048- and 4096-bit keys.

it.slashdot.org · 2026-09-25

Researchers find new method to forge RSA signatures without factoring keys

Cryptographer Nadia Heninger and colleagues have published research describing a novel technique that forges valid RSA digital signatures without first factoring the private key, a method previously assumed to be the only path to breaking RSA. The approach cuts the computational resources needed by orders of magnitude compared to earlier attacks, though it still requires far more computing power than most attackers could muster.

arstechnica.com · 2026-09-24