PQC Migration in Financial Services: A roadmap for Crypto Agility

Preparing for the quantum era begins with mobilizing the organization around a clear, strategic objective. It requires alignment across leadership, management, and operations on what postquantum cryptography (PQC) means for the business. Financial institutions must define clear strategic objectives for their post-quantum cryptography transition, map internal and external stakeholders who will be part of the journey, and appoint an executive lead to drive the program.

Mobilization also benefits from a clear objective: give the program a simple identity, explain the “why” in business terms, and keep communications regular and plainspoken. When engineers, risk teams, and business leaders hear a consistent message, PQC becomes part of everyday planning rather than a side initiative, and resistance drops.

Appointing an executive lead is critical because PQC migration is not just a technical upgrade, it is an enterprise-wide transformation that spans IT, security, risk, compliance, legal, procurement, and business operations. Without executive sponsorship, these functions often remain siloed. Executive leadership also signals to regulators, vendors, and internal stakeholders that PQC migration is a strategic priority rather than an optional technical initiative, strengthening governance and accountability from the start.

Build a cross-functional team

• Cybersecurity: Leads the technical assessment of current cryptographic controls, identifies vulnerable algorithms, defines security requirements, and ensures the migration aligns with threat models and industry standards.
• IT / Infrastructure & Architecture: Evaluates system dependencies, manages upgrades to protocols, applications, and hardware, and ensures that PQC and hybrid solutions can be integrated without disrupting business operations.
• Legal: Reviews the regulatory and contractual implications of cryptographic changes, updates agreements with third‑party providers, and ensures that data protection obligations are met during and after the transition.
• Compliance & Risk Management: Ensures alignment with regulatory expectations, supports risk assessments based on data sensitivity and longevity, and embeds PQC controls into existing governance and audit processes.
• Vendor Management / Procurement: Coordinates with external vendors, requests PQC readiness attestations, manages upgrade timelines, and ensures that critical suppliers meet the organization’s cryptographic requirements.

Together, these roles provide the technical depth, governance oversight, and operational coordination needed for a secure and efficient PQC transition. No single team can cover the full scope alone - crypto agility demands collaboration across the entire organization.

Build a cryptographic inventory

Using structured approaches such as a Cryptographic Bill of Materials (CBOM) helps bring clarity and consistency to this process. Similar to a software bill of materials, a CBOM provides a standardized way to document every cryptographic element within a system, including where it resides, how it is used, and which dependencies or third‑party components rely on it. This structure eliminates guesswork and ensures that teams across the organization apply a common language and format when cataloging cryptographic assets. This is crucial for complex, distributed financial environments.

Assess third-party dependencies

In addition, it is key to identify supply chain dependencies with all external vendors, service providers, and third-party platforms that interact with the organization’s systems and handle operations vulnerable to quantum attacks. Security is only as strong as the weakest link: even if your organization is compliant, a non-compliant software vendor can compromise your data, within or beyond your control. Key dependencies include cloud providers, payment processors, and core banking software vendors. Each introduces risk tied to their cryptographic readiness.  Organizations should assess vendor PQC compliance, request proof of migration efforts, and formalize requirements in contracts with clear deadlines for compliance.

Complete the diagnosis by mapping quantum-related risks, evaluating each algorithm and vendor dependency based on its vulnerability, potential business impact, and the effort required for migration. Align these insights with resource and budget planning to ensure realistic timelines. Establish cryptographic maturity baselines and benchmark against industry best practices to clarify readiness. With all this information obtained in this step, the organization can now plan a secure, efficient migration.

The formula:
X+Y<Z

This means:
The time your data needs to stay secure (X) plus the time it takes to migrate (Y) must be less than the time before quantum computers can break encryption (Z).

Use timing logic to prioritize

Institutions should combine this approach with risk assessments and maturity evaluations to identify systems and data that require early attention. This helps focus efforts where they have the greatest impact, reduces migration risks, and supports a balanced response to urgent security requirements.

Choose the right migration scenario

As part of your migration strategy, an important decision is to choose among several migration scenarios: whether to start with hybrid cryptography, move directly to full post quantum cryptography (PQC), or even explore Quantum Key Distribution (QKD). Hybrid cryptography uses both a traditional algorithm (like RSA or ECC) and a quantum safe algorithm simultaneously. This approach acts as a practical interim step by providing layered security: traditional cryptographic algorithms continue to protect against classical threats, while quantum-safe algorithms add protection against future quantum-enabled attacks. Full PQC replaces classical algorithms entirely with quantum safe alternatives but depends on ecosystem readiness to avoid operational or compatibility challenges. Quantum Key Distribution (QKD) represents a longer-term cryptographic approach that organizations may wish to monitor as the technology matures. It uses quantum physics to distribute encryption keys securely and requires specialized hardware and point-to-point connectivity, limiting its current applicability to a small number of high-value use cases.

Why hybrid can be a practical first step

In practice, hybrid cryptography means that keys from the classical algorithm and the PQC algorithm are combined so that both would need to be broken for the system to fail. Because PQC algorithms are still relatively new, there is a small possibility that weaknesses could be discovered in them over time. If that happens, the classical algorithm still provides protection against today’s threats. Hybrid cryptography therefore offers a balanced way to start the transition.

This approach helps mitigate “harvest now, decrypt later” risks, ensuring sensitive data remains secure even if classical encryption is broken in the future. Standards bodies like NIST and FS-ISAC recommend hybrid solutions for pilots and phased rollouts to support interoperability and reduce migration risk. However, it should be noted that hybrid configurations add complexity, computational overhead, hardware performance challenges on legacy systems, and potential downgrade vulnerabilities.

Where full PQC and QKD fit

Full PQC replaces classical cryptography end‑to‑end with quantum‑safe algorithms across protocols, applications, PKI/key management, and hardware, eliminating reliance on vulnerable primitives and offering long‑term protection against quantum attacks. However, moving everything to full PQC immediately is not usually advisable today. The ecosystem is not always ready in lockstep: many partners, suppliers, market infrastructures, and many customer platforms do not yet support PQC, and some profiles and enterprise‑grade implementations (e.g., TLS/X.509 variants, code‑signing, S/MIME) are still maturing. As a result, full PQC is best viewed as the destination, not the immediate starting point.

The final migration scenario, quantum Key Distribution (QKD), represents a fundamentally different approach to securing communications by using the principles of quantum physics to exchange encryption keys. Unlike PQC algorithms, which run on classical infrastructure, QKD requires dedicated hardware, such as quantumcapable fiber links or satellite connections, and provides security guarantees rooted in the laws of physics: any attempt to intercept the key exchange disturbs the quantum states and becomes detectable. While QKD offers very strong theoretical security, it is not a universal replacement for PQC. QKD only solves key distribution, not encryption itself; it is expensive to deploy at scale; it requires pointtopoint connections; and it does not integrate easily into cloudbased or highly distributed architectures. For most financial institutions, QKD is therefore best suited to niche, highvalue use cases, such as protecting highly sensitive interdatacenter links or communication between a limited number of fixed sites, rather than broad enterprise adoption. As standards and hardware mature, QKD may play a complementary role alongside PQC, but it is not a mainstream migration path for the wider cryptographic ecosystem today.

In summary, the strategy phase translates inventory insights into concrete decisions about when and how to migrate. By assessing how long data must remain secure, how long migration will take, and using conservative assumptions about quantum‑breaking timelines, institutions can identify which systems require early action. From there, organizations choose the most appropriate migration scenario: starting with hybrid cryptography for broad compatibility, planning full PQC as ecosystem readiness improves, or considering QKD for specialized, high‑value communication links. These choices create a clear, risk‑based path forward. With these strategic decisions in place, the final step is execution: turning plans into controlled, phased upgrades that bring the organization safely into the post‑quantum era.

Upgrade infrastructure and hardware

Execution involves upgrading cryptographic components across multiple layers of the enterprise in a structured and transparent way, in both hardware and software components. Due to the new algorithm’s computational demands, hardware upgrades or acceleration are often necessary to maintain performance and scale. PQC algorithms require more computational power and memory, particularly for key generation and signature verification. CPU cores, memory, and storage need to be upgraded or added to handle the increased load. Hardware upgrades are especially needed when using a hybrid solution, which doubles the load, or in high-volume environment, such as banking APIs or large data centers. Dedicated hardware components, such as HSMs, TPMs and self‑encrypting drives, serve as the root of trust for encryption, key management and signing. As organisations require larger keys, stronger signatures and faster processing, these devices must be upgraded to deliver higher performance and lower latency to handle the increased computational and storage demands.

Prepare software and engineering teams

Moving to full PQC or hybrid cryptography requires major software engineering changes. Any system that uses public‑key cryptography will need updates, ranging from cryptographic libraries and protocol stacks (such as TLS and IPsec) to PKI/Certificate Authorities, certificate formats, and code‑signing pipelines.

However, before planning cutovers, organizations should assess whether they have the skills and capacity to execute: do teams understand PQC algorithms and hybrid modes, certificate/profile changes, handshake behavior, and performance trade‑offs? Is there experience with HSM integrations, PKI refactoring, and large‑scale rollout automation? Based on that assessment, define a capability plan: upskill existing engineers (targeted training and hands‑on pilots), augment with specialists (crypto engineering, PKI, network/security protocol experts), and standardize development practices (test harnesses for interoperability and performance, secure configuration baselines, and automated compliance checks). Organizations should treat this as an engineering program with clear ownership, environments for safe experimentation, and repeatable pipelines, so updates can be delivered reliably across diverse platforms and services.

Embed Monitoring, Governance, and Third-Party Management

TDuring the execution phase, continuous monitoring, training, and periodic risk assessments are essential to keep migration efforts aligned with evolving threats and standards. Progress should be visible and controlled, with phased deployment across systems and vendors, supported by pilots, proof-of-concepts, interoperability testing, and clearly defined decision points.

The migration should be embedded within existing risk and change management frameworks, enabling business, IT, and external vendors to work together with clear responsibilities and rollback procedures. Vendor management requires particular attention. Organizations should assess the PQC readiness of their suppliers, include migration requirements in contractual agreements, and use CBOM analyses to identify hidden dependencies.

Close coordination with regulators and auditors helps ensure that timelines, reporting, and control measures remain aligned with applicable requirements. At the same time, lessons learned from pilots and implementations should be incorporated into updated plans and risk assessments. This creates a controlled and agile execution approach that strengthens long-term cryptographic agility while meeting today's regulatory expectations.