Each year, global quantum experts assess when quantum computers may break cryptographic security. This data can refine risk timelines and support business decision-making.

The Quantum Threat Timeline Report 2024 presents expert evaluations on the potential emergence of a quantum computer capable of breaking cryptographic schemes like RSA-2048 within 24 hours. Beyond simply presenting a forecast, the report details the reasoning behind these predictions and the factors influencing this evolving landscape.

However, discussions about quantum threats are no longer confined to hypothetical scenarios and corresponding timelines. Regulatory bodies across multiple jurisdictions now mandate the adoption of quantum-safe measures, regardless of individual opinions on when quantum threats will materialize.

The Key Indicator: Error Correction

Quantum computers have the potential to run advanced cryptanalysis algorithms capable of breaking modern cryptographic protocols. However, executing these algorithms against real-world cryptosystems requires sufficiently powerful quantum hardware. Current quantum systems remain constrained by their fragility, instability, and lack of scale. A quantum computer capable of overcoming these limitations and performing cryptanalysis at a meaningful level is usually called a cryptographically relevant quantum computer (CRQC).

One approach to overcoming this challenge is increasing quantum computing capacity by building logical qubits. A logical qubit, constructed from multiple physical qubits, offers a more reliable method for encoding and processing quantum information, even when individual physical qubits are prone to errors. Achieving this requires advancements in error correction, logical encoding, and the manipulation of quantum information. Scalability and modularity are also critical in determining whether quantum systems can be expanded into practical, large-scale applications capable of running cryptanalysis algorithms. Notably, 2024 saw significant progress in each of these areas.

•  The realization of a programmable quantum processor based on reconfigurable atom arrays, encoding and operating on up to 48 logical qubits (Bluvstein et al., 2024);

• The encoding of one logical qubit using ~100 physical qubits in a superconducting architecture goes beyond break-even and proves that logical coherence improves by utilizing more physical qubits for the encoding (Acharya et al., 2024).

• The preparation of entanglement between 12 logical qubits in a trapped-ion architecture and logical computation on a smaller set of logical qubits (Reichardt et al., 2024) expands and improves on previous demonstrations (da Silva et al., 2024).

In addition to hardware development, further developments in cryptanalysis algorithms could reduce the quantum resources—such as qubits or computational steps—required for successful cryptanalysis and accelerate the timeline.

From a hardware perspective, no single approach has emerged as the definitive path to scalable quantum computing. Superconducting qubits remain a strong contender, but cold-atom and trapped-ion technologies have made a notable impact in 2024, demonstrating unique advantages. Meanwhile, quantum optics and quantum spin systems in siliconhold promise due to their scalability, as they leverage existing semiconductor manufacturing processes.

Expert Predictions

The Quantum Threat Timeline Report 2024 survey found that nearly one-third of experts (10 out of 32) assigned a 50% or higher probability of a CRQC emerging within the next decade. Although risk tolerance varies across institutions, dismissing these findings outright is not advisable.

That said, some experts remain sceptical. A minority believe that breaking RSA-2048 could take more than 30 years. Interestingly, when asked what might prevent a CRQC from materializing within that timeframe, most respondents did not cite fundamental scientific barriers. Instead, they pointed to a series of formidable technical challenges that must still be overcome.