New classical computing attack weakens RSA encryption

As noted by Ars Technica, a recent research paper by researchers from the University of California San Diego and the Université de Lorraine has revealed a novel method using classical computing that significantly reduces the security of the RSA cryptosystem, a foundational element of modern encryption. While quantum computing has long been recognized as a future threat to RSA, this new attack bypasses the need for quantum capabilities by exploiting a different vulnerability.

The newly discovered attack allows for RSA signature forgery without factoring the encryption key, a method previously thought impossible or prohibitively expensive. While the attack currently poses little immediate practical threat due to high computational requirements, it drastically lowers the security level of "textbook" RSA implementations, particularly those using blind signatures. This includes protocols like Privacy Pass, used by major entities such as Apple and Cloudflare. The attack reduces the security of 1024-bit RSA keys to an unacceptable level and significantly weakens 2048- and 4096-bit keys.

Researchers emphasize that the attack's efficiency could be further improved with AI and GPUs. This development underscores the urgent need for the industry to transition to quantum-resistant cryptographic systems.

Source: Ars Technica