Preparation Is Key: How America Can Get Ahead of Q-Day – The National Interest Online
Referring to Q-Day, the day when quantum computers are powerful enough to break our current encryption, Arthur Herman, senior fellow at the Hudson Institute, once wrote the following: Q-Day is the term some experts use to describe when large-scale quantum computers are able to factorize the large prime numbers that underlie our public encryption systems... Ironically, the phrase Q-Day was also used for the testing of the first atom bomb in 1945.
Today, most of the world s digital communications rely on standardized encryption to protect against classical (the computers we currently use today) computing attacks. This encryption, sometimes referred to as public-key encryption, PKI (Public Key Infrastructure), RSA (Rivest Shamir Adleman) or ECC (Elliptic Curve Cryptography), is based on a single transaction of factoring a large number. This mathematical equation is all that stands between our data and our adversaries. For example, the numbers three and five multiply into the number fifteen and thus they are the factors. Factoring refers to being able to find two numbers that multiply into a much larger number. With large numbers it is a difficult and largely impossible task for classical computers to figure out; for example, 14,378,234 has factors of 806 17839. So far, all public-key encryption schemes have done an adequate job of protecting our data and communications, and we have also been able to increase the size of the numbers to be factored (also known as the key sizes) to stay ahead of the curve.
However, quantum computers are good at factoring large numbers. Quantum computers operate by using subatomic properties such as superposition, entanglement, and interference which enable a quantum computer to scale very rapidly, at an exponential rate. As a result, quantum computers have the power to crack encryption and solve the factoring problem. The fact is that we know mathematically from Peter Shors algorithm that quantum computers will absolutely break our current encryption unless we upgrade. What does that mean for the United States?
How Can Q-Day Happen?
When a sufficiently powerful quantum computer comes online (these can be referred to as cryptographically relevant quantum computers or CRQCs), whoever has access to such a computer will be able to decrypt any previously encrypted data. As an example, if an attacker has stolen and locally stored encrypted military secrets on their local serversa practice referred to as steal now, decrypt later (or SNDL) that we know is happening todayand these secrets are protected only by public-key encryption using the factoring that we discussed above, they will be decrypted by a CRQC. That attacker will now be able to decrypt all of that stored data and make use of it for whatever purposes they choose. Additionally, the same attacker could use that CRQC to attack communications that are currently occurring over the internet via the airwaves. The same powerful CRQC could be used to eavesdrop or steal data from radio transmissions, fiber transmissions, or any other communications that are using PKI. So, if that attacker has listening devices in a variety of geographic areas or regions, they could effectively unlock any data in transit moving over those communications lines.
When Will Q-Day Happen?
No one knows the exact date when Q-Day will happen. Some are predicting it will be around 2030, some say it will never happen, and others are estimating that we could have a CRQC in two to three years. We know that nation-states are investing billions of dollars in quantum computing, and it is estimated that China is spending upwards of $15 billion to build a quantum computer just to crack PKI. This effort utilizing over 1,000 programmers and scientists is formidable and should not be underestimated.
Our own government has been concerned and is now acting to mitigate the threat and consequences of a CRQC. The National Institute of Standards and Technology (NIST) has been studying and finalizing quantum-resistant algorithms. Recently the White House issued a Memorandum on Improving the Cybersecurity of National Security, Department of Defense, and Intelligence Community Systems which mandates that Within 180 days of the date of this memorandum (Jan. 19, 2022), agencies shall identify any instances of encryption not in compliance with NSA-approved Quantum Resistant Algorithms... Additionally, the United States Innovation and Competition Act of 2021 allocates over $12 billion, and contains specific language and funding for quantum cryptography and post-quantum classical cryptography.
Do not be fooled by what you see in the news or in public-facing articles. You can be sure that a nation-state attacker is not going to announce that they have a CRQC capable of dissolving PKI. Their incentive is to stay underground, harvesting as much data as they can before anyone notices.
Possible Q-Day Scenarios
So, what could happen if a U.S. adversary fully utilized a powerful quantum computer? We could see massive amounts of data being stolen and decrypted, financial system collapses, energy grid hacks, and even control over major military systems. The fact is that we are all leaving ever-increasing digital footprints and every company and government agency on this planet utilizes increasing amounts of digital capabilities and assets. Everything we do has a digital trace, and all data is now flowing and openly accessible though current standard encryption. Imagine if all that data was available to whoever had access to a CRQC? The power they would have would be so great that it is hard to imagine the damage that would be done and the global power that would be held.
Arthur Herman (mentioned above) conducted two formidable studies on what a single, successful quantum computing attack would do to both our banking systems and a major cryptocurrency. A single attack on the banking system by a quantum computer would take down Fedwire and cause $2 trillion of damage in a very short period of time. A similar attack on a cryptocurrency like bitcoin would cause a 90 percent drop in price and would start a three-year recession in the United States. Both studies were backed up by econometric models using over 18,000 data points to predict these cascading failures.
Another disastrous effect could be that an attacker with a CRQC could take control of any systems that rely on standard PKI. So, by hacking communications, they would be able to disrupt data flows so that the attacker could take control of a device, crashing it into the groundor even using it against an enemy. Think of the number of autonomous vehicles that we are using both from a civilian and military standpoint. Any autonomous devices such as passenger cars, military drones, ships, planes, and robots could be hacked by a CRQC and shut down or controlled to perform activities not originally intended by the current users or owners.
In their fictional book 2034: A Novel of the Next World War, Admiral James Stavridis and Elliot Ackerman portray a scenario where China can hack into U.S. military systems and shut down the global positioning system, weapon systems, and communications. This renders the U.S. military helpless and Chinese submarines simply destroy the U.S. Navys entire fleet in the South China Sea with uncontested torpedoes. In the book, all the U.S. militarys assets cannot communicate, and we are sitting ducks allowing China to create some significant destruction in the mainland United States. While not specifically mentioning a CRQC as the tool of destruction, it is completely within reason to think that a quantum computer powerful enough to crack all encryption and communications would be able to create this scenario.
Preparation Starts Now
So, with the above near-term threat, what can we do now to protect ourselves against such disasters?
First, I recommend that leadership, whether government, commercial or other, begin to look at existing cryptographic systems to understand where digital vulnerabilities exist. In many cases with large enterprises and government agencies, the cryptographic upgrade process from PKI to post-quantum cryptography (PQC) to protect systems could take years. PQC refers to the implementation of software-based cryptography and systems that are resistant to quantum attacks. Even with CRQCs, both communications and data would be resilient to quantum attacks since they use much more complex algorithms and systems than our standard PKI, which uses factoring. This move from PKI to PQC will be the largest upgrade cycle in computer history, and all public-key encryption needs to change to provide a completely quantum resilient ecosystem. Data in transit and at rest, and all devices will need to upgrade to PQC, which will reduce or mitigate the ability for quantum computers to crack encryption. Enterprise and government agencies can start now by testing PQC to understand how it works in their environments. Companies today provide PQC that can be tested in an enterprise or via the cloud. It is vital that all company leaders start the process of understanding how to move to a PQC worldthe future of U.S. national security depends on it.
Skip Sanzeri has been an entrepreneur since 1986 and currently is the Founder, Board Chair, CRO and COO at QuSecure, a top post-quantum cyber-security company using post-quantum cryptography and quantum key distribution to help secure the US military, government and commercial businesses. Founder and Board Chair Quantum Thought a leading venture studio focused on quantum computing applications and is also the Founder and Partner at Multiverse Capital. Skip is a co-author of Quantum Design Sprint: A Workbook for Designing a Quantum Computing Application and Disruptive Business Model.
Read more:
Preparation Is Key: How America Can Get Ahead of Q-Day - The National Interest Online
- Microsoft's claims over its quantum chip questioned in Nature article - BBC - June 26th, 2026 [June 26th, 2026]
- A new vision for quantum computing takes a big step forward, with new grant - YaleNews - June 26th, 2026 [June 26th, 2026]
- Uncertain quantum future presents existential threat to US military missions, DOD warns - DefenseScoop - June 26th, 2026 [June 26th, 2026]
- University of Maryland Grant Targets Quantum and AI Tools for Cancer Research - The Quantum Insider - June 26th, 2026 [June 26th, 2026]
- A Quantum Leap: The Technology Trying to Reinvent the Computer - marketscreener.com - June 26th, 2026 [June 26th, 2026]
- Meeting Trump's 2030 Quantum Deadline Will be Expensive, Complex - Dark Reading - June 26th, 2026 [June 26th, 2026]
- Trump Executive Orders Home in on Useful Quantum Computing - govtech.com - June 26th, 2026 [June 26th, 2026]
- Will operationalized quantum computing hit the public soon? - IT Brew - June 26th, 2026 [June 26th, 2026]
- Pentagon Sets Hard 2031 Deadline for Quantum-Resistant Encryption, Names Nuclear Command at Risk - Tech Times - June 26th, 2026 [June 26th, 2026]
- New R Street Study Warns U.S. Critical Infrastructure Is Running Out of Time to Prepare for Quantum Threats - R Street Institute - June 26th, 2026 [June 26th, 2026]
- The U.S. Government Is Betting Billions on Quantum Computing. These 3 Stocks Are the Biggest Winners. - The Motley Fool - June 26th, 2026 [June 26th, 2026]
- Quantum Computing Stocks IonQ, Rigetti Computing, and D-Wave Quantum Sent Shockwaves Through Wall Street With This $857 Million Warning - Yahoo... - June 26th, 2026 [June 26th, 2026]
- Trump Wants to Aggressively Fast Track Quantum Computing Projects - Yahoo Finance - June 26th, 2026 [June 26th, 2026]
- Trumps Orders Intended to Advance US Quantum Computing Industry - The Well News - June 26th, 2026 [June 26th, 2026]
- Quantum Computing Stocks IonQ, Rigetti Computing, and D-Wave Quantum Sent Shockwaves Through Wall Street With This $857 Million Warning - The Motley... - June 26th, 2026 [June 26th, 2026]
- The PQC Silicon Is Here Today for Tomorrows Quantum Threats - EE Times - June 26th, 2026 [June 26th, 2026]
- Texas A&M Supercomputer Named Most Powerful Among US Universities - HPCwire - June 26th, 2026 [June 26th, 2026]
- Executive orders lift Colorados quantum stocks and aspirations - Colorado Public Radio - June 24th, 2026 [June 24th, 2026]
- A new quantum computer sets a high watermark for accuracy are we on the verge of a big breakthrough? - The Conversation - June 24th, 2026 [June 24th, 2026]
- Bull and Alice & Bob Partner up to Bring Quantum Computers into HPC - The Quantum Insider - June 24th, 2026 [June 24th, 2026]
- Why Investors Are Finally Separating Quantum Computing Winners From Losers - 24/7 Wall St. - June 24th, 2026 [June 24th, 2026]
- With major conference in town, Mass. seeks to boost quantum computing efforts - The Boston Globe - June 24th, 2026 [June 24th, 2026]
- Quantum Computing Is Finally Here. But What Is It? - Bloomberg.com - June 24th, 2026 [June 24th, 2026]
- Trump signs executive orders to 'supercharge' quantum computing - ABC News - Breaking News, Latest News and Videos - June 24th, 2026 [June 24th, 2026]
- Trump Fast-Tracks Quantum Computing With New Executive Orders - Barron's - June 24th, 2026 [June 24th, 2026]
- Quantum computer furthers healthcare research at Cleveland Clinic - Spectrum News - June 24th, 2026 [June 24th, 2026]
- Chicago Missed the Tech Boom. Quantum Computing Gives It a Second Chance. - WSJ - June 24th, 2026 [June 24th, 2026]
- Quantum computing is often seen as a risk to bitcoin. Now Trump wants to develop it. - CoinDesk - June 24th, 2026 [June 24th, 2026]
- Trump Seeks to Boost Quantum Computing With New Executive Orders - WSJ - June 24th, 2026 [June 24th, 2026]
- The Mathematical Tools Trailblazing the Quantum Future - Simons Foundation - June 24th, 2026 [June 24th, 2026]
- D-Wave Quantum: Trumps Orders Make This Speculative Buy Worth Watching (NYSE:QBTS) - Seeking Alpha - June 24th, 2026 [June 24th, 2026]
- Executive orders seek to hasten quantum computingand guard against its use - Defense One - June 24th, 2026 [June 24th, 2026]
- Physicist reacts to Trump executive order calling for a quantum computer - NBC News - June 24th, 2026 [June 24th, 2026]
- 3 Quantum Computing Stocks With More Upside Than SpaceX - Yahoo Finance - June 24th, 2026 [June 24th, 2026]
- Quantum Computing Stocks Mixed Amid Trump Executive Orders, 2028 Target - Investor's Business Daily - June 24th, 2026 [June 24th, 2026]
- The US government wants a working quantum computer by 2028 and quantum-resistant encryption by 2031 - TechSpot - June 24th, 2026 [June 24th, 2026]
- Donald Trump Signs Quantum Computing Orders What Could It Mean for Bitcoin and XRP? - Yahoo Finance - June 24th, 2026 [June 24th, 2026]
- QuantWare and Maybell Partner to Maximize Compute-Per-Watt Performance of VIO-40K systems - The Quantum Insider - June 24th, 2026 [June 24th, 2026]
- Quantum computing is finally here. But what is it? - BusinessWorld Online - June 24th, 2026 [June 24th, 2026]
- White House Looks to Speed Up Transition to Quantum Computing with Pair of Executive Orders - PYMNTS.com - June 24th, 2026 [June 24th, 2026]
- The post-quantum EO is an important milestone. Now its time to get to work - The Cloudflare Blog - June 24th, 2026 [June 24th, 2026]
- Quantum Motion and NVIDIA Simplify Molecular Modeling on Quantum Computers - ForkLog - June 24th, 2026 [June 24th, 2026]
- The Path to Quantum Advantage Is Built on Readiness, Not Hype, IBM Report Suggests - The Quantum Insider - June 22nd, 2026 [June 22nd, 2026]
- Is the Dogecoin Burn Address Really Safe from Quantum Threat? - Cryptonews.net - June 22nd, 2026 [June 22nd, 2026]
- GCS highlights exascale, AI factories and hybrid computing at ISC 2026 - Scientific Computing World - June 22nd, 2026 [June 22nd, 2026]
- Amazon Says Commercially Useful Quantum Computers Are Moving Closer To Becoming a Reality - International Business Times - June 22nd, 2026 [June 22nd, 2026]
- QBTS vs. RGTI vs. IONQ: Which Quantum Computing Stock Could Deliver the Biggest Returns? - TipRanks - June 19th, 2026 [June 19th, 2026]
- Xanadu Quantum vs. IonQ: The Better Quantum Computing Stock Buy for 2026 - Yahoo Finance - June 19th, 2026 [June 19th, 2026]
- AMD Advances the Hybrid Future of Quantum Computing - AMD - June 19th, 2026 [June 19th, 2026]
- Algorand Wants to Be Quantum-Proof by 2027, Three Years Before the NSA - International Business Times - June 19th, 2026 [June 19th, 2026]
- Sooner than expected? Useful quantum error correction promised for 2028. - Ars Technica - June 19th, 2026 [June 19th, 2026]
- QuEra targets fault-tolerant quantum computing with new Libra system and expanded AWS partnership - New Electronics - June 19th, 2026 [June 19th, 2026]
- Atom Computing and Nu Quantum Partner to Scale Neutral Atom Quantum Computers - The Quantum Insider - June 19th, 2026 [June 19th, 2026]
- Quantum hyperdimensional computing can work 500 times faster than other methods - Phys.org - June 19th, 2026 [June 19th, 2026]
- Algorand Plans to Be Ready for Quantum Computing Threat by End of 2027 - Decrypt - June 19th, 2026 [June 19th, 2026]
- New Industry Study Finds Quantum Computing Has Entered a Capability Era, With Early Movers Building an Advantage Later Entrants Will Struggle to Close... - June 19th, 2026 [June 19th, 2026]
- Prediction: This Quantum Computing Stock Is Going to Plummet in the Second Half of 2026 - Yahoo Finance - June 19th, 2026 [June 19th, 2026]
- Cleveland Clinic & IBM Forum Charts AI And Quantum Impact On Detection - Quantum Zeitgeist - June 19th, 2026 [June 19th, 2026]
- Diraq Expands U.S. Presence with Palo Alto Office - The Quantum Insider - June 19th, 2026 [June 19th, 2026]
- Xanadu Quantum vs. IonQ: The Better Quantum Computing Stock Buy for 2026 - The Motley Fool - June 19th, 2026 [June 19th, 2026]
- Almost every encrypted secret being protected today banking records, classified government cables is expected to become readable within the next... - June 19th, 2026 [June 19th, 2026]
- This AI Learned the Laws of Physics and Could Accelerate Quantum Computing Breakthroughs - SciTechDaily - June 19th, 2026 [June 19th, 2026]
- Helios quantum computer tops 99.9% fidelity rates for one- and two-qubit operations - Phys.org - June 19th, 2026 [June 19th, 2026]
- This Beaten-Down Quantum Stock Is Gaining Fans. Theyre Starting to Figure It Out. - Barron's - June 16th, 2026 [June 16th, 2026]
- Are useful and error-free quantum computers only two years away? - New Scientist - June 16th, 2026 [June 16th, 2026]
- Quantum Pulse Ventures Expanded Photonic Infrastructure Platform Boosts Optical Connectivity Via Scalable, Low Loss Integrated Optical Applications -... - June 16th, 2026 [June 16th, 2026]
- Quobly secures 115M to advance silicon-based quantum computers - Evertiq - June 16th, 2026 [June 16th, 2026]
- The U.S. government is betting $2 Billion on quantum computing, and the defense side can't keep up - CoinDesk - June 16th, 2026 [June 16th, 2026]
- IonQ, Rigetti, and D-Wave Are Surging Again. Is Quantum Computing Finally Real? - The Motley Fool - June 16th, 2026 [June 16th, 2026]
- Quantum Threat to Crypto Is Not Here Yet, but Coinbase Advisory Board Says the Time to Prepare Is Now - The Quantum Insider - June 16th, 2026 [June 16th, 2026]
- Researchers Develop Theory for Improved Quantum Error Correction with Non-Isometric Codes - Quantum Zeitgeist - June 16th, 2026 [June 16th, 2026]
- 5 Best Computer Hardware Stocks to Buy for the Next 5 Years - Insider Monkey - June 16th, 2026 [June 16th, 2026]
- QuEra Announces 2028 Fault-Tolerant Quantum Computer and Expanded Multi-Year Strategic Collaboration with AWS - The Quantum Insider - June 16th, 2026 [June 16th, 2026]
- QuEra Announces 2028 Fault-Tolerant Quantum Computer and Expanded Multi-Year Strategic Collaboration with AWS - PR Newswire - June 16th, 2026 [June 16th, 2026]
- IQM Quantum Computer Goes Live at Supercomputing Center CINECA in Italy, Boosting National Compute Infrastructure and Research - Yahoo Finance - June 16th, 2026 [June 16th, 2026]
- Quera Announces 2028 Fault-Tolerant Quantum Computer And Expanded Multi-Year Strategic Collaboration With AWS - TradingView - June 16th, 2026 [June 16th, 2026]
- Quantum Computing Looks Like Nvidia in 2019. This Could Be the Generational Buy of the Decade. - Barchart.com - June 12th, 2026 [June 12th, 2026]
- AI helps reveal large-scale quantum effects hidden in stacked atomic sheets - Phys.org - June 12th, 2026 [June 12th, 2026]
- Quantum Computing Threat Elevates Cryptography to Board-Level Risk Oversight - WSJ - June 12th, 2026 [June 12th, 2026]
- Why Google (GOOGL) Rejected the $2 Billion U.S. Quantum Funding Program Over Speed Concerns - TipRanks - June 12th, 2026 [June 12th, 2026]