Rapid advancements in quantum computing are bringing about one of the most fundamental technological shifts in cryptography and data security.
As the era of PQC, or post-quantum cryptography, draws nearer, the need for quantum-resistant cryptography across enterprises will skyrocket. These changes are already influencing roadmaps and compliance timelines. This is not surprising, as the complexity of implementing quantum-resistant cryptography demands a phased, risk-aligned approach. And it’s one that you need to begin today.
Two pillars of such an approach include adapting existing infrastructure for crypto-agility and introducing hybrid certificates that are positioned by data criticality. Preparing for the changes to come will help ensure a smooth transition from legacy cryptographic algorithms to the post-quantum cryptography of the future.
Conduct a Risk-Based Inventory
The first step in implementing quantum-resistant cryptography is conducting a full inventory of the organization’s PKI. This includes digital certificates, security keys, protocols, data libraries, and all devices tied into the PKI trust chain. Once catalogued, each asset should be classified according to three key factors:
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Sensitivity of the data it protects
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Expected lifetime of the data or how long it must remain confidential
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Risk and impact of potential data exposure
Top priorities for quantum-resistant protection typically include:
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Root and issuing Certificate Authority (CA) keys
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Client authentication systems
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IoT firmware signing platforms
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Long-term document signing systems
These assets are critical in the PKI ecosystem and carry severe operational risks if compromised.
Begin by identifying the cryptographic algorithms in use, prioritizing high-risk assets. Pay close attention to certificate expiration timelines (some may last 5 to 10 years, potentially extending beyond NIST’s PQC rollout timeframe.) Monitoring evolving standards and aligning certificate lifecycles accordingly is essential.
Systems interfacing with external partners require special attention. These edge systems need coordinated updates for hybrid cryptography compatibility and ongoing testing to ensure continued functionality during the transition.
Match Protection to Risk Tier
The number of assets any organization handles is enormous, necessitating triage of implementation and a tiered approach to protection. The classifications made at the inventory stage will guide application of cryptographic protections proportionally to each asset’s sensitivity and risk of exposure.
The following three categories give a broad idea of what protections to prioritize for your data, with an understanding that each organization’s assets are unique and the needs may differ:
- Protection required now: Systems with long-term confidentiality requirements (such as legal, financial, healthcare, and strategic IP), since these are at the greatest risk of Harvest Now Decrypt Later attacks.
- Transition via hybrid or PQC certificates: Medium-risk systems that still require classical certificate-only validation for compatibility.
- Agile classical cryptography that can switch algorithms quickly: low-risk data and short-lived transactions.
At each implementation phase for each risk tier, continue to document your security posture to meet regulatory requirements.
Take a Hybrid Approach to Quantum-Resistant Cryptography
A hybrid approach, which involves hybrid certificates that can support both legacy and PQC algorithms, is a practical and pragmatic stepping stone to post-quantum cryptography. Yet, organizations should not rely completely on this strategy because the depreciation of soon-to-be-legacy algorithms will necessitate the phase-out of vulnerable PKI.
A hybrid certificate is a certificate that contains two algorithm signatures: one classical and one post-quantum, ensuring backwards compatibility with existing clients while providing quantum-resistant encryption where it is already supported. This dual-stack structure allows for a gradual transition that can be implemented in phases. You can start issuing hybrid certificates in internal systems where you control both the client and the server, such as the mutual TLS (mTLS) within your network. Before updating certificates and replacing them with hybrid ones in other systems, make sure to know what specific types of hybrid certifications these systems support.
Another important thing to note is that hybrid certificates tend to increase in size compared to legacy certificates due to the post-quantum algorithm byte count, which can be significant in some post-quantum signatures such as ML-DSA. These can potentially break in legacy systems, so a phased approach is one of the safest ways to proceed.
Most well-architected PKIs can be upgraded incrementally, without the need to replace everything all at once. To make the process easier, consider CAs that support cryptographic profiles that include hybrid and PQC algorithms, and integrate policy engines that can assign algorithms—whether classical, hybrid, or PQC—based on use case, environment, or system tier.
At this stage, certificate automation is not just a nice-to-have for an enterprise but a necessary reality that ensures the correct renewal, rotation, and revocation of certificates at scale. It becomes even more vital given the significant increase in complexity that hybrid deployments introduce. Automation will also help you adapt to ongoing changes and respond to unknowns. For this reason, avoid using hard-coded cryptographic tokens or keys, which will make downstream changes challenging and significantly more costly.
Prioritize Interoperability and Compliance
Interoperability is one of the top ongoing challenges of PKI. Here are tips to help ensure that interoperability is woven into the fabric of your PQC-ready PKI system:
- Avoid using proprietary algorithms and protocols unless there are no alternatives
- Follow NIST’s PQC standardization process closely, as formats and APIs are still evolving, and what ends up being the industry standard by 2030-2035 is still unknown
- Track IETF efforts on X.509 hybrid certificate extensions and TLS 1.3 integration for PQC key exchange
- Build an internal compatibility matrix and run cross-platform tests, especially if you serve multiple geographic or regulatory domains
- Monitor your relevant regulatory bodies to stay ahead of compliance mandates; many are publishing PQC readiness frameworks and sector-specific guidance to help companies prepare.
Lead with Governance, Training, and Clear Communication
PQC adoption and crypto-agility demand an enterprise-wide shift in policy, protocols, and mindset. Assign ownership for PQC transition planning to a cross-functional group involving stakeholders in security architecture, PKI operations, compliance, and procurement, who will then be able to communicate the roadmap towards quantum-resistant cryptography clearly across business and technical domains. PQC prep is a trust continuity effort, and framing it as such will help secure funding and buy-in from executive leadership.
Support the staff in this transition as well. Train developers and security engineers on hybrid formats, algorithm performance tradeoffs, and common compatibility pitfalls. As the PQC rollout gets on the way, update your cryptographic policies to reflect new hybrid issuance rules, algorithm deprecation timelines, and exception handling processes.
Conclusion
The road to implementing quantum-resistant cryptography may be long and complex, but preparation, the right mindset, and choosing the right partners will go a long way in ensuring a smooth PQC transition.
Keyfactor is a trusted partner ready to lead your organization through the PQC transition. Together, we can protect your infrastructure from the adversaries of tomorrow while maintaining continuity, compliance, and trust today. Begin your crypto-agility journey today – our team is here to help you.
