A new cryptographic attack has been discovered that can compromise RSA encryption through signature forgery rather than factorization, marking a significant conceptual departure from decades of cryptographic assumptions. The method employs a variant of the number field sieve algorithm combined with an oracle property in certain cryptographic protocols to gather sufficient information for breaking the encryption.
The attack’s practical impact varies by key size. Against deprecated 1024-bit RSA keys, the technique required only a handful of months on an academic computing cluster, dramatically less demanding than factoring-based approaches that would necessitate resources typically available only to major technology companies or nation-states. The method reduces security levels from the mandated minimum of 128 bits to 265 bits for 1024-bit keys, 290 bits for 2048-bit keys, and 2119 bits for 4096-bit keys. Researchers noted these levels could decrease further since their implementation used only hand-coded solutions without artificial intelligence or graphics processing units.
The vulnerability affects only blind-signature or textbook RSA implementations, sparing the vast majority of deployed RSA systems that use PKCS or PSS padding formats. However, some real-world applications do employ the vulnerable variant, notably Privacy Pass, a privacy-preserving authentication protocol used by Apple and Cloudflare. Attacking Privacy Pass would theoretically require an attacker to request tokens approximately 2^43 times, a volume comparable to Cloudflare’s daily network traffic. Regular key rotation in most Privacy Pass deployments provides additional protection against successful attacks.
Cryptography experts characterize the immediate practical threat as limited but significant. The discovery has intensified discussions about transitioning away from RSA toward quantum-resistant alternatives, a process already underway within the cryptographic community. The research underscores that the security foundations previously considered foundational to RSA may require fundamental reassessment.
Article Attribution | Read More at Article Source
Article summary produced by Claude AI