Encryption & Key Management,
Next-Generation Technologies & Secure Development,
Security Operations
French Startup Estimates RSA-2048 Could Fall in Three Days With 23,000 Qubits
A groundbreaking announcement from the French startup Alice & Bob has stirred significant interest in the tech community, as the company claims it can dismantle widely used internet encryption protocols in an astonishingly short timeframe. Specifically, they assert that RSA-2048 encryption could be broken in as few as three days, and blockchain cryptography might be compromised in even less time—approximately one hour—utilizing an innovative approach that demands significantly fewer quantum resources than previously estimates.
According to the international startup, which operates out of both Paris and Boston, the mathematical encryption RSA-2048 can be effectively factored via Shor’s algorithm, requiring fewer than 23,000 physical qubits in optimal conditions. This revelation is particularly noteworthy as it stands in stark contrast to Google Quantum AI’s earlier prediction from 2025, which estimated a staggering requirement of around 1 million qubits for the same task.
The remarkable advancement arises from Alice & Bob’s architecture that employs a specialized type of error-resistant physical qubit—termed a cat qubit. This design not only enhances performance but also minimizes the number of physical qubits needed to create logical qubits that can rectify computational errors. This strategic shift allows Alice & Bob to achieve cost efficiency and speed without compromising the integrity of their operations.
Théau Peronnin, the Chief Executive Officer of Alice & Bob, conveyed the significance of these advancements, stating, “Estimates of the resources needed to run [Shor’s] algorithm have been steadily falling as the field has developed better approaches to error correction and algorithm design. This latest estimate doesn’t just push that frontier; it changes the paradigm altogether.” His assertion encapsulates the essence of the rapid evolution in quantum computing technology.
As the race continues among quantum computing laboratories to develop the first cryptographically effective computer—one that can break encryption swiftly without requiring excessive resources—different approaches have emerged. Techniques range from utilizing trapped ions to experimenting with neutral atoms and silicon spin qubits. Ultimately, the success of these endeavors relies heavily on striking a delicate balance between the number of qubits necessary for error correction and the speed at which computations can be executed.
Shor’s algorithm, widely regarded as a hallmark of quantum computing, presents a well-defined mathematical challenge while showcasing a clear quantum advantage. Consequently, researchers are actively addressing this complex issue, seeking to refine their methodologies.
Reflecting on past benchmarks, a prominent researcher from Google Quantum AI, along with a collaborator, previously estimated in 2019 that factoring a 2,048-bit RSA integer could be accomplished within a mere eight hours, requiring 20 million noisy physical qubits. Fast forward six years, and this estimate was reduced to less than 1 million qubits needed to complete the task in under a week.
Peronnin highlighted that Alice & Bob’s journey of progress mirrors these trends, with its estimated requirements for cat qubits needed to break RSA-2048 diminishing from an earlier forecast of 350,000 in 2023 to 100,000 a year later, and now narrowing to an impressive 23,000. Furthermore, for breaking elliptic-curve cryptography—which secures transactions on popular blockchain networks like Bitcoin and Ethereum—the company has estimated only 30,000 qubits could suffice to facilitate this in roughly an hour.
This latest leap in capability capitalizes on the inherent advantages of cat qubits that mitigate errors at the hardware level, deploys more efficient error-correcting codes, and implements a refined version of Shor’s algorithm specifically optimized for use with cat qubits. As Peronnin concluded, “To our knowledge, no published architecture is smaller at this runtime, which puts us at the frontier of size and speed together.”
The implications of these developments extend beyond mere academic interest. The implications are profound; the rapid evolution of quantum computing could initiate a paradigm shift for encryption protocols globally. The prospect is not just theoretical; it carries real-world consequences for organizations dependent on conventional cryptographic methods to safeguard sensitive information.
Experts like Anders Indset, host of the Quantum Economy podcast, have noted that while Alice & Bob has achieved a substantive milestone, their work does rest on some uncertain foundations. The concept of near-perfect qubits introduces a level of theoretical speculation that warrants cautious optimism. The performance and scalability of these cat qubits in practical applications remain to be fully validated through peer review and real-world testing.
Despite those caveats, the broader implication underscores a critical urgency for industries and institutions to adapt. Indset advises that the rapidly advancing mathematics of quantum computing may outpace the design and migration of cryptographic systems—an outcome that could have dire repercussions for businesses and sensitive data protection.
As observers and experts look ahead, they recognize a looming threat that is multifaceted. It’s not merely about identifying a single “Q-Day” when quantum computing fully takes hold; rather, it’s the risk of ‘harvest now, decrypt later.’ Data captured today may remain secure for the time being, only to be exposed years down the line. For instance, a quick compromise of a cryptographic key over the course of three days may be inconsequential in real-time transactions, but it poses severe risks for objectives like medical records, state secrets, and intellectual property requiring long-term confidentiality.
Moreover, dormant Bitcoin stored within older pay-to-public-key addresses presents another intriguing target for potential quantum attacks. According to Doug Finke, Chief Content Officer at Global Quantum Intelligence, these static assets, which reside in wallets that have not executed transactions for years, may be particularly vulnerable to quantum threats. They lack the sense of urgency found in ongoing Bitcoin transactions, which generally have a 10-minute confirmation window. In contrast, older holdings could remain exposed, potentially allowing malicious actors a window of opportunity lasting an hour to exploit vulnerabilities.
In summary, the rapid advancements in quantum computing, bolstered by efforts from prominent companies such as Google and others within the field, paint a picture where asymmetric encryption could be on the verge of being compromised. The potential financial repercussions for unprepared enterprises could be monumental, emphasizing the critical need for organizations to initiate quantum-safe remediation programs within their IT infrastructures as soon as possible. As the landscape evolves, vigilance and proactive action will be paramount in the protection against emerging quantum threats.