Is cryptography, the guardian of our digital security, crumbling in the face of quantum computers' power? A group of Chinese researchers appears to have reached a milestone by breaking RSA encryption using a D-Wave processor.
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RSA, the foundation of many digital security protocols, relies on a dual-key system to encrypt and decrypt information. For a long time, its robustness seemed unbreakable by classical computers, which would take millions of years to break even the simplest systems.
RSA encryption is based on a highly complex mathematical problem: the factorization of large numbers into prime numbers. This problem is easy to solve if the private key is known but extremely difficult without it. However, Chinese researchers claim to have succeeded in breaking a 50-bit RSA, a simplified version of this encryption, by exploiting qubits in a D-Wave quantum computer. They used a technique called "quantum annealing," which can evaluate multiple solutions simultaneously, thus speeding up the solving process.
However, RSA encryption used in most modern communications is infinitely more complex. Current RSA keys, ranging from 1024 to 2048 bits, would require quantum computing power still far beyond today's technologies.
Nevertheless, this advancement serves as an alarm signal. By breaking a small-scale RSA, the researchers pave the way for cracking more complex encryptions. In response to this potential vulnerability, post-quantum cryptography is emerging as a sustainable solution. Developed by scientists, it employs algorithms resistant to quantum attacks, making data inviolable even for future quantum computers.
These new techniques, however, present significant implementation challenges. Replacing current systems with post-quantum algorithms requires rigorous testing and sometimes a complete overhaul of existing infrastructures. The financial sector and intellectual property might be the first to adopt these post-quantum protection measures, anticipating potential attacks and growing cyber threats.
Thus, while quantum computers seem limited in their ability to crack large-scale encryption, research continues to strengthen the security of sensitive data in our rapidly evolving digital world.
What is post-quantum cryptography?
Post-quantum cryptography refers to a new generation of security algorithms designed to resist attacks from quantum computers. Unlike current systems like RSA or AES, these new protocols are designed to remain unbreakable, even in the face of quantum computing power.
Quantum computers, indeed, can perform complex calculations much faster than traditional computers, thus threatening encryption based on asymmetric keys. Post-quantum cryptography uses innovative mathematical techniques to protect sensitive information from this new threat.
Currently being developed by scientists worldwide, this cryptography could become essential for data security, particularly in banking and military sectors, within a few decades.
How does quantum annealing work?
Quantum annealing is a calculation method used by some quantum computers to solve complex problems. Rather than testing each solution sequentially, quantum annealing allows testing several possibilities simultaneously thanks to the properties of qubits, the fundamental units of quantum computers.
Unlike classical computers, which handle bits representing either 0 or 1, quantum computers use qubits, which can be in multiple states simultaneously due to the phenomenon of superposition. Thus, qubits enable quantum annealing to explore multiple paths to find optimal solutions. This technique is particularly effective for optimization problems, where the goal is to find the best configuration among a large number of possibilities.
Thanks to quantum annealing, some computational problems, like breaking encryption, can be solved much faster than with classical computers. However, this method remains limited for the time being and is still not capable of handling modern large-scale encryption.
Article author: Cédric DEPOND