Security News > 2023 > January > Chinese researchers' claimed quantum encryption crack looks unlikely
The paper, titled "Factoring integers with sublinear resources on a superconducting quantum processor," suggests that the application of Claus Peter Schnorr's recent factoring algorithm, in conjunction with a quantum approximate optimization algorithm, can break asymmetric RSA-2048 encryption using a non-fault tolerant quantum computer with only 372 physical quantum bits or qubits.
The speculation has been that orders of magnitude more qubits, in conjunction with robust error correction at scale, may allow future quantum computers to run Peter Schor's algorithm - not to be confused with the similarly named Schnorr - quickly, on very large numbers, thereby breaking RSA encryption.
In 2019, researchers published a paper [PDF] claiming that 2048-bit RSA integers could be factored in about eight hours given a quantum computer with 20 million noisy qubits.
Symmetric cryptographic algorithms, like AES-256, are considered to be more resistant to quantum computers, so the application of Grover's algorithm [PDF] in a quantum system isn't expected to alter the cryptographic landscape.
The paper from 24 researchers in China might have remained a matter for those well-versed in advanced mathematics, cryptography, and quantum computing - a fairly small set of people - but for the fact that it got noticed by cryptographer Bruce Schneier.
Schneier did not take a position on the paper, but the following day The Financial Times took notice in an article titled, "Chinese researchers claim to find way to break encryption using quantum computers."