A team of 24 Chinese researchers has reportedly achieved a breakthrough by using a quantum computer to crack RSA encryption — a widely used public-key cryptosystem that secures everything from banking to cryptocurrency transactions. The claim was published in December 2022 on a preprint server, sparking intense debate among cryptographers and cybersecurity experts.
The Claim and Its Context
RSA (Rivest–Shamir–Adleman) relies on the difficulty of factoring large prime numbers. A 2048-bit key is considered secure against classical computers for decades to come. However, the Chinese researchers assert that their quantum algorithm successfully factored a 2048-bit integer, effectively breaking the encryption. In September 2022, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) had already warned that the post-quantum era was imminent, urging organizations to prepare for the eventual demise of current encryption standards. If confirmed, this advance would allow governments to read each other's secrets, as noted by security expert Roger Grimes in a statement to the Financial Times: “It’s a huge claim — it would mean that governments could crack other governments' secrets. If it’s true — a big if — it would be one of the biggest things ever in computer science.”
Skepticism from the Cryptography Community
Leading cryptographer Bruce Schneier has been cautious. In an analysis, Schneier pointed out that the paper relies on a disputed algorithm proposed by German mathematician Peter Schnorr. “We have no empirical proof that the [new] quantum algorithm overcomes the Schnorr scaling problem,” Schneier told the Financial Times. “There’s no reason to believe it won’t — but there’s no reason to believe it will.” Other experts note that the paper has not undergone peer review, and the recorded computations have not been independently verified. The Google Groups discussion also shows divided opinions, with many pointing out technical flaws in the statistical analysis used by the authors.
Implications for Cryptocurrency
The potential of quantum computers to break elliptic curve cryptography (ECC) — the backbone of Bitcoin and other cryptocurrencies — has long worried the crypto community. Bitcoin evangelist Andreas Antonopoulos once famously stated that if a government possessed such a device, “The last thing they are going to use that on is Bitcoin. Because the moment you use it on Bitcoin, you announce to the world we have quantum cryptography that can break [the] elliptic curve — guess what happens? Your nuclear rivals upgrade their cryptography very easily and try to implement quantum-resistant cryptographic algorithms.” Indeed, many blockchain projects are already exploring post-quantum signatures, such as those based on lattice or hash-based schemes.
The Broader Race
Regardless of whether this particular claim holds up, the race to build a practical quantum computer capable of breaking real-world encryption is accelerating. Major governments and corporations — including IBM, Google, and China’s own research institutes — are pouring billions into quantum computing. Schneier concluded that while this paper might turn out to be another false alarm, “someday that bet will be wrong.” The world must prepare for a post-quantum security landscape, whether that day comes in five years or fifty.
Industry standards bodies such as the U.S. National Institute of Standards and Technology (NIST) have already begun standardizing post-quantum cryptographic algorithms. In July 2022, NIST selected four candidate algorithms, including CRYSTALS-Kyber and CRYSTALS-Dilithium, which are designed to resist attacks from both classical and quantum computers. The transition to quantum-safe infrastructure will take years, but the latest claim — even if disputed — underscores the urgency.