French quantum computing startup Alice & Bob says it can factor RSA-2048 in as fast as three days using fewer than 23,000 physical qubits, roughly 40 times fewer than Google Quantum AI's 2025 estimate of one million qubits. The company attributes the reduction to a special error-resistant "cat qubit" that lowers the number of physical qubits needed for logical error correction. In a best-case scenario the same cat-qubit architecture could break elliptic-curve cryptography protecting Bitcoin and Ethereum with about 30,000 qubits in roughly an hour. Alice & Bob’s estimate follows a trend of shrinking resource needs: cat-qubit requirements fell from 350,000 in 2023 to 100,000 a year later and now 23,000. The preprint has not been peer-reviewed, and the scalability of the cat qubits in real-world conditions remains uncertain. 1