Post-quantum cryptography: why your first step is a cryptographic inventory

A sufficiently powerful quantum computer would break the public-key cryptography that protects most of today’s internet traffic, payments and digital signatures. No one can say exactly when. Governments and standards bodies have stopped waiting, and the work they ask for first is not exotic: know where your cryptography is.

“Harvest now, decrypt later”

Attackers can record encrypted traffic today and decrypt it once quantum capability exists. Data that must stay confidential for many years, such as health records, identity documents or long-term contracts, is already exposed to this risk. That is why migration timelines start now, not when the first capable machine appears.

The standards are ready

On 2024-08-13, NIST approved its first three post-quantum standards: FIPS 203 (ML-KEM, for key establishment), FIPS 204 (ML-DSA) and FIPS 205 (SLH-DSA), both for digital signatures (NIST). NIST has also published a draft plan for retiring quantum-vulnerable algorithms such as RSA and elliptic-curve cryptography (NIST IR 8547, draft).

Canada’s roadmap

The Canadian Centre for Cyber Security published the federal government’s migration roadmap on 2025-06-23 (Cyber Centre). Federal departments were to develop an initial migration plan by April 2026, report progress annually, complete migration of high-priority systems by the end of 2031 and of remaining systems by the end of 2035. The roadmap is written for federal departments, but suppliers to government and regulated industries should expect the same questions to reach them.

PCI DSS already asks for the first step

Two PCI DSS v4 requirements, mandatory since 2025-03-31, lay the groundwork (PCI DSS v4.0.1):

• Requirement 4.2.1.1: an inventory of the trusted keys and certificates used to protect card data in transit.
• Requirement 12.3.3: cryptographic cipher suites and protocols in use are documented and reviewed at least once every 12 months, including an inventory of what is used and where, monitoring of industry trends on their continued viability, and a documented strategy to respond to anticipated changes (analysis).

That “strategy to respond to anticipated changes” is, in practice, the start of a post-quantum plan. The PCI SSC has also begun discussing cryptographic agility on its blog.

A practical starting plan

1. Build a cryptographic inventory. Protocols, cipher suites, certificates, keys, hardware security modules, libraries and the cryptography inside third-party and cloud services.
2. Rank by data lifetime. Prioritize systems protecting data that must remain confidential beyond 2030.
3. Ask your vendors. Payment processors, HSM vendors, cloud and SaaS providers: what is their post-quantum roadmap, and when will they support the NIST algorithms?
4. Design for agility. Avoid hard-coded algorithms so you can switch without rebuilding systems.
5. Fold it into existing reviews. Your annual 12.3.3 review is a natural checkpoint.

Ubitrak reviews cryptographic inventories as part of PCI DSS assessments, and Accel GRC can track the migration plan. Contact us.

Sources

• Canadian Centre for Cyber Security: Roadmap for the migration to post-quantum cryptography for the Government of Canada (ITSM.40.001)
• NIST: Post-quantum cryptography FIPS approved (FIPS 203, 204, 205)
• NIST IR 8547 (initial public draft): Transition to post-quantum cryptography standards
• PCI SSC Document Library (PCI DSS v4.0.1)
• Chad M. Barr: Key considerations for PCI DSS v4.0.1 requirements 4.2.1.1 and 12.3.3
• PCI SSC: PCI Perspectives blog