A French start-up claims quantum computers could break RSA-2048 encryption in days, far fewer qubits than previously thought.
Quantum threat to encryption revealed
A French start-up named Alice & Bob has estimated that a quantum computer with 22,593 qubits could break the RSA-2048 encryption in three days. This estimate is significantly lower than the nearly one million qubits previously estimated by Google. Impact on online security
The RSA-2048 encryption is widely used to protect online banking, emails, and digital signatures. According to the same report, a Bitcoin key could be broken in just over an hour using a quantum computer with a similar number of qubits. Quantum computing's mathematical edge
The Shor algorithm, developed in 1994 by American mathematician Peter Shor, is a calculation method designed for quantum computers that can decompose a very large number into prime factors much faster than classical computers. This poses a significant threat to current cryptographic systems. Bitcoin and quantum vulnerabilities
Alice & Bob's researchers also examined ECDLP-256, the mathematical problem behind elliptic curve cryptography used in Bitcoin and Ethereum transactions. They estimate that breaking this encryption would require less than 30,000 qubits and 62 minutes. Network defenses against attacks
However, the Bitcoin network validates a new block of transactions approximately every ten minutes, which would likely confirm a payment before an attack could succeed. The researchers' findings consider not only the number of qubits but also the total resources mobilized. Efficient quantum computing
Using chat qubits, a specialty of Alice & Bob, the team reduced the number of qubits required by more than half compared to a previous estimate from 2023. They replaced the repetition code with more efficient LDPC-cat codes and optimized the addition process in the Shor algorithm. Resource requirements for quantum attacks
According to Alice & Bob's projections, a million standard qubits would require 625 large quantum computers, occupying 33,000 square meters and consuming 500 MW of electricity. With chat qubits, only 15 machines would be needed, occupying 800 square meters and consuming 12 MW of electricity. Future of quantum-resistant encryption
The start-up acknowledges that engineering challenges remain considerable but predicts that hardware and needs will converge at the beginning of the 2030s. American and British recommendations aim for a complete transition to post-quantum cryptography by 2035. Call for immediate action
Cryptanalyst Antoine Joux and Ali El Kaafarani, CEO of PQShield, advocate for immediate deployment of post-quantum encryption on critical infrastructures. Alice & Bob emphasizes that new algorithms will only gain confidence by withstanding attacks from cryptanalysts.
