Q‑Day.org exists to cut through the hype around “Q‑Day” – the moment quantum computers can break today’s public‑key cryptography.
I’m Marin Ivezic, founder of Applied Quantum and a longtime writer at PostQuantum.com. Seeing how much noise distorts timelines, I built this site to share a transparent, model‑driven way to forecast the quantum risk. You’ll find a curated set of my most relevant articles from PostQuantum.com, a plain‑English walkthrough of the assumptions behind my own forecast, and a simple Q‑Day Estimator that lets you adjust the key parameters and generate your own timeline. The goal isn’t to hand you a date; it’s to equip you with a method you can stress‑test and refine.
It’s time to mark a controversial date on the calendar: 2030 is the year RSA-2048 will be broken by a quantum computer. That’s my bold prediction, and I don’t make it lightly. In cybersecurity circles, the countdown to “Q-Day” or…
A series of breakthroughs, from improved quantum computing algorithms to enhanced error correction and quantum hardware scaling, signals a shift in the quantum computing landscape. In my opinion. These developments indicate that quantum supremacy and cryptographically relevant quantum computing (CRQC) are transitioning from primarily scientific challenges to practical engineering problems. I track all significant research papers and engineering milestones that inform my prediction in a timeline listed here:
For three decades, Q-Day has been “just a few years away.” I want to show you how to make your own informed prediction on when Q-Day will arrive. Counting physical qubits by itself is misleading. To break RSA you need error‑corrected logical qubits, long and reliable operation depth, and enough throughput to finish within an attack‑relevant time window.
Benchmarking quantum capabilities for cryptography is both critical and challenging. We can’t rely on any single metric like qubit count to tell us how near we are to breaking RSA-2048. A combination of logical qubit count, error-corrected circuit depth, and operational speed must reach certain thresholds in unison. Existing benchmarks – Quantum Volume, Algorithmic Qubits, etc. – each address parts…
Read about the approach and relevant attributes in the two articles above. Then use the CRQC Readiness Benchmark (Q‑Day Estimator) tool below to turn assumptions into a defensible, crypto‑specific forecast. The tool converts four inputs, LQC (logical qubits), LOB (logical operations budget), QOT (logical ops/sec), and an annual growth factor, into a Composite CRQC Readiness Score and a projected “Q‑Day” (when week‑scale factoring of RSA‑2048 becomes practical). Start with Conservative / Median / Aggressive presets, then tweak to match vendor claims or your own view of roadmaps and error‑correction progress. This is intentionally focused on cryptographic breakability, not generic “quantum advantage,” so it may diverge from headline qubit counts.
An interactive way to explore how close we may be to a cryptographically relevant quantum computer (CRQC) for breaking RSA-2048.
Adjust assumptions below to see how the projected Q‑Day shifts.
Methodology & discussion.
Disclaimer: this tool is for experimentation and scenario analysis only.
Scenarios:
Load a starting scenario, then tweak parameters to explore.
Count of error-corrected (logical) qubits available.
x
Reliable logical operations available (circuit depth).
x
Logical operations per second (throughput).
Annual capability multiplier for the composite score.
Advanced formula (optional)
Composite CRQC Readiness Score
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Projected Q-Day
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Projected CRQC Readiness score over time
Score 1.0 ≈ quantum capability to factor RSA-2048 in about one week. Adjust inputs and formula to explore scenarios. Estimates are illustrative only.
Logical Qubit Capacity (LQC): number of error-corrected, stable qubits available to run long algorithms. In vendor materials, look for keywords like “logical qubit”, “error-corrected qubit”, or “fault-tolerant qubit”. Roadmaps sometimes state targets such as “100+ logical qubits by 2029.”
Logical Operations Budget (LOB): reliable count of logical gate operations (circuit depth) your system can execute before failure. In announcements, look for “gate fidelity”, “circuit depth”, or “error-corrected layers.” Higher two-qubit fidelities and longer coherence indicate larger LOB.
Quantum Operations Throughput (QOT): how many logical operations per second your machine can execute (akin to clock speed). Vendors may refer to “ops per second”, “cycle time”, or metrics like CLOPS.
Score = (LQC / LQC₀) × (LOB / LOB₀) × (QOT / QOT₀). By default LQC₀=1,000; LOB₀=10¹²; QOT₀=10⁶. Score 1.0 ≈ capability to factor RSA-2048 in ~1 week. You can tweak these baseline constants here.
Growth factor: assumed year-over-year multiplier of the composite capability score. Example: 2.0 means doubling per year; 3.0 means tripling. Look for roadmap wording like “doubling yearly”, “10× every five years”, or similar. This drives the projected Q‑Day when score reaches 1.0.
I will try and compare my proposed CRQC Readiness Benchmark with QTT, highlighting fundamental differences in methodology, assumptions, and philosophy,…
This proposal outlines a composite, vendor‑neutral “CRQC Readiness” indicator. It intentionally avoids one‑number vanity metrics (like only counting qubits) and…
Quantum computing holds the potential to revolutionize fields where classical computers struggle, particularly in areas involving complex quantum systems, large-scale…
