The landscape of cybersecurity is changing dramatically. Attack and defense have already changed due to artificial intelligence. This change is now being accelerated by quantum technology, which presents what I have long referred to as a double-edged sword: strong new defensive capabilities on the one hand and an existential cryptographic threat on the other.
Q-Day—the time when cryptographically relevant quantum computers can crack popular public-key algorithms like RSA and elliptic-curve cryptography—is getting closer, or in some estimates, it’s already very close. Sophisticated actors and nation-state enemies are not holding back. They are using “harvest now, decrypt later” tactics, gathering encrypted data now with the specific goal of decrypting it as quantum technology advances. Sensitive information with a long lifespan, such as financial records, government secrets, intellectual property, personal data, and communications related to critical infrastructure, is especially vulnerable. This reality compromises the foundation of Zero Trust architectures—strong authentication, encryption both in transit and at rest, and identity verification.
However, quantum technology is not only dangerous; it also provides resources to improve resilience. Additionally, it provides resources to improve resilience. Businesses that consider quantum only as a potential issue run the risk of disastrous exposure. Those who get ready now and adopt both quantum-enhanced defenses and post-quantum cryptography will be in a better position in the coming years.
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The Quantum Danger to Present-Day Cryptography
The mathematical hardness assumptions that underpin a large portion of contemporary public-key cryptography are threatened by quantum computing’s capacity to execute algorithms like Shor’s at scale. This is not just lab-based theoretical conjecture. Many experts believe that advances in algorithms, hardware, and error correction have shortened timelines. The risk is increased by the potential for quantum decryption combined with agentic AI systems that can prioritize high-value encrypted repositories, automate reconnaissance, and plan mass harvesting.
Zero trust relies on strong cryptographic foundations and ongoing verification. The model as a whole need to be recalibrated when those foundations deteriorate. The ability to switch cryptographic primitives without interfering with operations, or crypto-agility, becomes crucial. Organizations need to create migration plans that are in line with NIST post-quantum cryptography standards, identify long-lived sensitive data, inventory cryptographic assets, and develop the operational capacity to adjust as quantum capabilities develop. These days, both national security and business continuity depend on quantum readiness.
Five Ways Cybersecurity Could Benefit from Quantum Technology
Quantum technologies offer defensive opportunities even as the threat necessitates immediate attention. Here are five useful ways that quantum approaches can improve cybersecurity, based on advancements in quantum sensing, communications, optimization, and hybrid systems:
1. Quantum Key Distribution for Communications with High Assurance and Detectability
By utilizing the concepts of quantum mechanics, Quantum Key Distribution (QKD) makes it possible to detect any attempt to intercept key material by upsetting the quantum state. QKD provides a route to more secure key exchange that supplements post-quantum cryptography in hybrid deployments in high-stakes settings, such as government, critical infrastructure, and financial systems. Although there are still practical issues with infrastructure, integration, and distance, there is a lot of promise for certain high-value links.
2. Quantum Sensing for Improved Situational Awareness and Threat Detection
Compared to classical systems, quantum-enhanced sensors provide higher sensitivity and accuracy. These features can enhance supply-chain visibility, navigation integrity, monitoring of the physical and digital environments, and anomaly detection. Quantum sensing improves the capacity to detect threats more quickly and accurately in critical infrastructure and national security contexts.
3. Defensive Analytics through Quantum Optimization and Simulation
Quantum and hybrid quantum-classical systems are well-suited for complex optimization and simulation problems that classical computers find difficult. Threat modeling, resource allocation in security operations centers, red-team and purple-team exercises that mimic quantum-era attacks, and quicker behavioral anomaly analysis of large-scale datasets are all areas in which security teams can use these strengths. Improved optimization supports more robust architectures under dynamic threat conditions.
4. Promoting Quantum-Resistant and Crypto-Agile Frameworks in Zero Trust
The quantum challenge itself speeds up the incorporation of post-quantum cryptography into communications layers, endpoint security, identity and access management, and data-at-rest encryption. Zero Trust is strengthened by incorporating PQC and designing for cryptographic agility, which guarantees that ongoing verification is based on principles that will hold true as quantum capabilities advance. Systematic inventory and cryptographic bills of materials become essential to operations.
5. Making Hybrid Secure Infrastructures and Physics-Based Resilience Possible
Prototypes for quantum networking, photonic architectures, and related systems suggest more resilient digital infrastructures that go beyond simple computing power. By combining quantum-derived techniques with classical post-quantum algorithms, hybrid approaches can lessen the dependence on mathematical hardness assumptions that are susceptible to quantum attack. These advancements enable more robust or self-defending network foundations for critical systems and the Web3 era.
Big Data complex graph. Quantum computing universe. Cyber space of AI technology.
Suggestions for Implementation
Businesses cannot afford to wait for timelines to be perfectly clear. Practical actions consist of:
• Make a comprehensive cryptographic inventory and give high-value, long-lasting data priority.
• While increasing crypto-agility, create and test migration strategies to NIST-standardized post-quantum algorithms.
• For high-priority use cases where physics-based security adds quantifiable value, assess quantum sensing and QKD.
• Incorporate quantum awareness into workforce upskilling, AI-enhanced detection and response, and Zero Trust evolution.
• Encourage cross-sector intelligence sharing and public-private cooperation because AI and quantum threats won’t respect organizational boundaries.
The threat landscape and defensive toolkit are already changing due to the convergence of AI and quantum. In this environment, resilience requires proactive leadership, ethical governance, ongoing innovation in security procedures, and a clear understanding that technology is outpacing readiness and policy in many organizations.
Success will depend on those who take action today, rethink tactics, embrace crypto-agility, and use quantum capabilities where they improve defense. people who put off exposing their most valuable assets to risk. The quantum age is not far off. We should begin preparing now.
Supporting Sources and Further Reading
• Chuck Brooks, “How AI & Quantum Computing Will Transform Zero Trust Cybersecurity,” GovCon Wire / Executive Mosaic (June 2026).
• Chuck Brooks, “How AI and Quantum, And Space Are Redefining Cybersecurity,” Forbes (January 2026).
• Chuck Brooks, “AI, Quantum And The New Cybersecurity Framework Imperative,” Forbes (June 2026).
• Chuck Brooks, “AI And Quantum Are Impacting Cyber Risk. Boards And CISOs Must Prepare,” Forbes (July 2026).
• Chuck Brooks, “Q-Day: Catastrophic For Businesses Ignoring Quantum-Resistant Encryption,” Forbes (February 2026).
• NIST Post-Quantum Cryptography standardization efforts (FIPS 203, 204, 205 and related guidance).
• Discussions of harvest-now-decrypt-later strategies and Q-Day timelines in cybersecurity literature and expert analyses (including estimates referenced in public commentary by researchers such as Michele Mosca).
• McKinsey Quantum Technology Monitor reports on quantum computing, communication, and sensing market trajectories.
This article was originally published on Forbes.com
