Chinese scientists have discovered that a quantum computer developed by Canadian company D-Wave is capable of effectively breaking a widely used encryption method.

The research team, led by Wang Chao from Shanghai University, used a D-Wave quantum machine to target Substitution-Permutation Network (SPN) structured algorithms, which perform a series of mathematical operations to encrypt data.

SPN techniques form the core of the Advanced Encryption Standard (AES), one of the most widely used encryption methods today. The research paper discusses two technical approaches to potentially crack RSA encryption using quantum computing.

The first approach detailed in the paper involves using D-Wave’s quantum computer entirely. Researchers presented it with complex problems, including an optimization challenge and a search problem, which the quantum computer solved using specialized mathematical models called Ising and QUBO.

The second approach combines traditional computing techniques with quantum power. Researchers layered classical cryptographic methods, such as the Schnorr signature algorithm and Babai rounding (which are used to improve security), with quantum computing’s ability to process vast amounts of data at high speed. This hybrid method enabled the attack to surpass what traditional computers are capable of achieving.

The team said this marks “the first time that a real quantum computer has posed a real and substantial threat to multiple full-scale SPN structured algorithms in use today.”

However, it’s important to note that the quantum attack was conducted on a 22-bit key, which is relatively short compared to what is used in real-world encryption. In practical applications, much longer keys, typically 128-bit or 256-bit, are used and they’re more difficult to crack, even for a quantum computer.

Anticipating this potential threat, some leading VPNs have already begun developing encryption protocols that are resistant to quantum attacks. For example, ExpressVPN’s Lightway protocol incorporates quantum-resistant cryptography based on the Kyber algorithm, which uses highly complex mathematical structures that are designed to withstand both traditional and quantum computer attacks.