There's a new way to break RSA that's faster than anything we've seen before
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Researchers have discovered a novel method to break RSA encryption that is significantly faster than previous techniques, challenging the long-held belief that factoring large integers is the only way to compromise the system. Led by Nadia Heninger, the team developed a signature forgery attack using a variant of the number field sieve algorithm, which drastically reduces the computational resources needed to breach RSA keys. This new approach lowers the security level for 1024-bit, 2048-bit, and 4096-bit keys to 2^65, 2^90, and 2^119 operations respectively, falling well below the 128-bit threshold recommended by major security agencies. Despite this conceptual breakthrough, the attack currently poses little practical threat because it only targets blind-signature implementations, also known as textbook RSA. Most modern systems use PKCS or PSS padding, which eliminates the specific vulnerability exploited by this method. However, some real-world applications like Privacy Pass, used by Apple and Cloudflare, still rely on vulnerable implementations, though key rotation mitigates immediate risks. The findings underscore the urgency for the industry to migrate away from RSA toward quantum-resistant alternatives.
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