Enterprise Preparation for Q-Day
Posted June 20, 2025 by Sayers

Quantum computers are set to revolutionize computing and yet they also pose a significant risk to current encryption methods. This event is often referred to as Q-Day. On Q-Day, quantum computers will be able to crack the most widely used forms of encryption, potentially leading to the sudden unlocking of the world’s secrets, making everything from emails to financial systems vulnerable.
The unsettling reality is that the timeline for when Cryptographically Relevant Quantum Computers (CRQC) will be available is uncertain, however industry leaders and analysts are stating this could be within five years.
“Asymmetric encryption is in almost all software, billions of devices worldwide and most of the communications over the internet. Yet by 2029, advances in quantum computing will make asymmetric cryptography unsafe and by 2034 fully breakable. “Harvest-now, decrypt-later” (HNDL) attacks may already exist.” -Gartner.
CRQC will be able to decrypt data in hours instead of years, which is a huge leap from current capabilities. Data with a long lifespan, like personal, healthcare, financial, government data, or intellectual property, is particularly vulnerable.
Post-Quantum Cryptography (PQC) recognizes that advanced quantum computers will compromise many existing public-key cryptographic algorithms, including RSA and Elliptic Curve Cryptography (ECC), due to Shor’s algorithm’s ability to factor large numbers and compute discrete logarithms efficiently. This has profound implications for:
- Data Confidentiality: Encrypted data, including sensitive personal information, financial records, and state secrets, could be decrypted.
- Digital Signatures: The authenticity and integrity of digital documents and software updates could be compromised.
- Secure Communication: Protocols like TLS/SSL that secure internet traffic would be vulnerable.
- Cryptocurrency: The security of many blockchain technologies relies on current public-key cryptography.
Recommendations
To mitigate these risks, it’s crucial to develop and implement a PQC strategy. This involves transitioning to quantum-resistant algorithms and ensuring that cryptographic systems are updated. Implementing a modular cryptographic architecture, or Crypto-Agile Strategy, allows for future updates and better cryptography integration.
Steps to Prepare for the Post-Quantum Era
Proactive preparation is key to mitigating the risks associated with the PQC transition. Organizations should not wait until the threat is imminent.
1. Inventory Your Cryptographic Assets
The first and most crucial step is to understand where and how cryptography is used throughout your organization. This includes:
- Identifying all applications, systems, and devices that use encryption, digital signatures, or key exchange.
- Cataloging the specific algorithms, key lengths, and protocols in use.
- Determining data sensitivity and required lifespan of protection. This “Cryptographic Bill of Materials” (CBOM) will form the basis of your migration plan.
2. Stay Informed and Monitor Standards
Keep abreast of developments from standardization bodies like NIST (USA), ETSI (Europe), and other international groups. Understand the selected algorithms, their properties, and the timelines for their formal standardization and adoption. Follow guidance from cybersecurity agencies.
3. Develop a Prioritized Migration Plan
Based on your crypto inventory and risk assessment, develop a phased migration strategy.
- Prioritize high-risk systems: Focus first on systems protecting long-lived sensitive data (due to HNDL risk) and critical infrastructure.
- Identify dependencies: Understand how different systems interact and plan accordingly.
- Set realistic timelines and milestones.
4. Embrace Crypto-Agility
Design and update systems to be crypto-agile. This means engineering systems so that cryptographic algorithms can be easily replaced or updated without significant architectural changes or service disruptions. This is vital not just for the current PQC transition but for future cryptographic migrations as well.
5. Experiment and Test PQC Algorithms
Begin evaluating and testing the standardized PQC algorithms in non-production environments.
- Assess their performance impact on your specific systems and applications.
- Gain familiarity with their implementation requirements.
- Test interoperability between different PQC-enabled components. NIST and other organizations provide resources and test vectors for this purpose.
6. Educate and Train Your Teams
Invest in training for your IT, security, and development teams on quantum computing, PQC, and the implications for your organization. Building internal expertise is crucial for a successful transition.
- Crypto Center of Excellence (CCoE): Establish a CCoE to coordinate cryptographic policy, retain valuable metadata, and provide expertise to development teams.
7. Engage with Your Vendors
Communicate with your hardware, software, and service providers about their PQC roadmaps.
- Inquire about their plans for supporting standardized PQC algorithms.
- Understand their timelines and how they will ensure the security of their offerings.
- Factor vendor PQC readiness into your procurement decisions.
8. Budget and Allocate Resources
The transition to PQC will require significant financial and human resources. Start budgeting for necessary hardware/software upgrades, development effort, training, and potential consulting services.
9. Review and Update Security Policies and Practices
Your organization’s security policies, data retention policies, and incident response plans will need to be updated to reflect the quantum threat and the adoption of PQC.
Act Now!
The transition to post-quantum cryptography is not merely an upgrade; it’s a fundamental evolution of our digital defenses against a future class of threats. While the journey presents considerable risks and challenges, from performance considerations to the sheer complexity of migration, these are manageable with foresight, planning, and a commitment to action. The time to prepare is not when quantum computers are breaking encryption, but now, while we can proactively build a resilient, quantum-resistant digital world.