Post-Quantum Cryptography: Why Preparation Needs to Start Now

Quantum computers are not yet capable of compromising the cryptography that protects modern communications, digital signatures, and key exchange at scale. That does not mean organizations should wait for a sufficiently powerful quantum system to appear before they begin preparing.

The reason is practical. Cryptography is embedded in applications, network devices, certificates, virtual private networks, software libraries, cloud services, and third-party systems. Discovering these dependencies, testing new mechanisms, and planning the transition can take years.

On 13 August 2024, the U.S. National Institute of Standards and Technology, NIST, published the first three finalized Federal Information Processing Standards, FIPS, for post-quantum cryptography and encouraged organizations to begin preparing for the transition. Although these standards were developed within the U.S. federal framework, they have broad international relevance and influence the development of global technologies, products, and security practices.

In Europe, the European Commission Recommendation of 11 April 2024 established the basis for a coordinated transition. In June 2025, the NIS Cooperation Group published a European roadmap stating that Member States should begin the transition by the end of 2026, while critical infrastructure should move to post-quantum protection as early as possible and no later than the end of 2030.

The topic is already becoming part of practical planning for security, architecture, procurement, and risk management.

What is post-quantum cryptography?

Post-quantum cryptography, PQC, refers to cryptographic mechanisms designed to resist both known classical attacks and attacks from sufficiently powerful quantum computers.

These mechanisms do not require a quantum computer to operate. They can be deployed on standard computing infrastructure, but they rely on mathematical problems for which no efficient classical or quantum solutions are currently known.

It is important to distinguish between three concepts.

Quantum computing uses principles of quantum mechanics to perform certain types of computation.

Quantum cryptography uses quantum properties to protect or distribute keys, for example through Quantum Key Distribution, QKD.

Post-quantum cryptography uses algorithms that run on conventional computers but are designed to remain secure even in the presence of a large-scale quantum computer.

For most organizations, the immediate practical focus is post-quantum cryptography and the ability to introduce it gradually and in a controlled manner.

Which parts of today’s cryptography are exposed?

Future quantum systems are particularly relevant to widely used public-key cryptography, including:

• RSA, Rivest-Shamir-Adleman
• ECC, Elliptic Curve Cryptography
• DSA, Digital Signature Algorithm
• cryptographic key exchange
• digital signatures
• parts of the digital certificate infrastructure

These mechanisms support secure web connections, virtual private networks, device authentication, software signing, and digital identity validation.

Symmetric algorithms such as AES, Advanced Encryption Standard, are not affected in the same way that quantum algorithms may affect RSA and ECC. In their case, the discussion usually focuses on a reduction in the effective security level and the need for appropriate key sizes and an updated risk model.

This distinction matters. Organizations cannot apply the same migration step to every cryptographic dependency. They need an inventory that shows where each mechanism is used and what purpose it serves.

Why the risk matters now

Harvest now, decrypt later

In a Harvest Now, Decrypt Later, HNDL, scenario, an attacker collects encrypted data today even though they cannot yet read it. The data is stored with the expectation that future advances in quantum technology may allow it to be decrypted.

This is especially relevant for information that must remain confidential for a long period:

• medical and genetic data
• government and diplomatic communications
• critical infrastructure information
• industrial intellectual property
• financial and contractual documents
• personal data with a long sensitivity period

The risk depends not only on when a practical quantum attack becomes possible. It also depends on how long the information must remain protected.

Systems with long operational lifecycles

Industrial, energy, transport, and medical environments often use equipment for 10, 15, or more years.

Some of these devices do not allow cryptographic algorithms to be replaced easily, or they depend on outdated libraries, certificates, and unsupported software.

An organization purchasing a system today should verify:

• whether the vendor has a plan for post-quantum support
• whether algorithms can be replaced through software updates
• whether the hardware has enough resources for new mechanisms
• how long the device and its software will remain supported
• whether the vendor can provide a clear migration roadmap

Post-quantum readiness is therefore also a procurement, contractual, and vendor-management issue.

Digital signatures and the software supply chain

The transition affects more than data confidentiality.

Digital signatures prove the authenticity of software, documents, updates, and devices. If a signing mechanism becomes unreliable, an organization may face difficulties verifying whether:

• an update comes from the legitimate vendor
• a digital document has been altered
• a device is connecting to a legitimate system
• a software package or firmware image is authentic

This is why NIST published separate standards for key establishment and digital signatures.

What has NIST standardized?

The first three FIPS standards for post-quantum cryptography are:

• FIPS 203, specifying ML-KEM, Module-Lattice-Based Key-Encapsulation Mechanism
• FIPS 204, specifying ML-DSA, Module-Lattice-Based Digital Signature Algorithm
• FIPS 205, specifying SLH-DSA, Stateless Hash-Based Digital Signature Algorithm

ML-KEM is intended for establishing a shared cryptographic key. ML-DSA and SLH-DSA are digital signature mechanisms.

The terminology matters. FIPS 203, FIPS 204, and FIPS 205 are standards. ML-KEM, ML-DSA, and SLH-DSA are the mechanisms specified by those standards.

What is changing in the United States and Europe?

On 22 June 2026, the United States issued the Executive Order “Securing the Nation Against Advanced Cryptographic Attacks.”

It establishes a deadline of 31 December 2030 for the use of applicable post-quantum standards for key establishment in certain high-value and high-impact federal systems. The deadline for migration to post-quantum digital signatures is 31 December 2031.

The order also provides for the development of requirements for certain federal contractors through amendments to the Federal Acquisition Regulation, FAR.

These requirements apply to the U.S. federal government and related suppliers. They do not automatically apply to all European organizations.

Their effect may nevertheless extend to international technology vendors, federal contractors, and supply chains working with U.S. institutions.

The European Union is following its own coordinated approach. The European roadmap sets the start of the transition by the end of 2026 and prioritizes the migration of critical infrastructure by the end of 2030.

These dates do not mean that every system must replace its algorithms immediately. They mean that organizations should begin with visibility, ownership, planning, and dependency assessment.

Where should an organization begin?

1. Define ownership and scope

Post-quantum readiness is not solely the responsibility of the information security team.

It affects:

• information security
• infrastructure and networking
• software architecture
• risk management
• legal and regulatory functions
• procurement
• vendor management

A useful first step is to appoint an owner and establish a small working group to coordinate the inventory, prioritization, and long-term planning.

2. Build a cryptographic inventory

The organization should identify where cryptography is used across:

• applications and web services
• virtual private networks
• TLS, Transport Layer Security, certificates
• keys and key stores
• digital signatures
• network devices
• cloud integrations
• software libraries
• devices and firmware
• third-party solutions

The inventory should show more than which algorithm is used. It should also document:

• what function it performs
• who owns the system
• what data it protects
• how long that data must remain protected
• whether the mechanism can be replaced
• which vendor the change depends on

NIST treats cryptographic discovery and inventory as a core part of migration to post-quantum cryptography.

3. Identify long-lived sensitive data

Not all data has the same risk horizon.

Information that loses value after a few days has a different profile from medical records, strategic plans, classified communications, or intellectual property that must remain confidential for years.

The cryptographic inventory should therefore be linked to data classification. This allows the organization to identify which systems are most exposed to the Harvest Now, Decrypt Later scenario.

4. Prioritize external communications and critical systems

A practical approach is to assess encrypted connections that cross untrusted networks first:

• site-to-site connections
• partner communications
• remote access
• cloud integrations
• data center interconnections
• critical VPN tunnels
• externally accessible applications

These communication paths often carry sensitive information and may be more exposed to interception and long-term collection.

5. Review vendor plans

Post-quantum readiness also depends on the vendors providing:

• network equipment
• cloud services
• operating systems
• certificate and identity services
• applications
• software libraries
• industrial and medical devices

Relevant questions include:

• Which post-quantum standards will the product support?
• When will support become available?
• Will new hardware be required?
• Will hybrid modes be available?
• How will existing certificates and keys be migrated?
• What performance and interoperability changes should be expected?

Crypto-agility instead of a one-time migration

Crypto-agility is the ability of an organization to replace algorithms, certificates, keys, and cryptographic libraries without redesigning entire systems.

This matters because post-quantum mechanisms have different operational characteristics. They may use larger keys and signatures, require more processing power or memory, and affect connection-establishment times.

A single mechanism may not be suitable for every application, device, and communication channel.

The goal is to build an architecture that supports controlled change, testing, and gradual deployment. This reduces dependence on a specific algorithm or vendor and makes future adaptation easier as standards evolve.

A practical framework for the first 90 days

Preparation can begin as a limited readiness project without an immediate large-scale migration.

Days 0–30: ownership and working group

• appoint an owner
• include security, infrastructure, architecture, risk, procurement, and legal functions
• define critical systems and data
• clarify objectives and reporting

Outcome: clear process ownership and a shared organizational scope.

Days 30–60: cryptographic inventory

• identify algorithms, protocols, certificates, and keys
• review VPN, TLS, digital signatures, and external dependencies
• find legacy or unsupported mechanisms
• link cryptography to the data it protects

Outcome: visibility into the main cryptographic dependencies.

Days 60–90: prioritization and roadmap

• assess external communications
• identify systems containing long-lived sensitive data
• begin discussions with key vendors
• identify testing requirements
• prepare an initial migration roadmap

Outcome: clear priorities for further assessment and preparation.

A similar 90-day framework is presented in the Fortinet material on practical post-quantum readiness shared by the DIAMATIX team.

How Fortinet technologies can support preparation

Post-quantum readiness begins with process, visibility, and a realistic assessment of dependencies. Technology platforms can support execution, especially in environments with many network devices and encrypted external connections.

Fortinet documents support for post-quantum mechanisms in IPsec, Internet Protocol Security, key exchange on FortiGate, including hybrid models. The company also documents post-quantum capabilities for TLS 1.3 in FortiWeb and additional PQC functions in newer FortiOS versions.

According to Fortinet:

• FortiManager with FortiAI-Assist can support configuration review and the preparation of checklists for unsafe or outdated cryptographic mechanisms
• FortiAnalyzer can support the measurement and reporting of cryptographic risk
• FortiGate can support the protection of external encrypted communications through post-quantum and hybrid IPsec mechanisms
• Fortinet Security Fabric can connect management, analysis, and phased configuration changes within a common operational model

These capabilities do not replace a cryptographic inventory, data classification, or vendor assessment. They can support discovery, measurement, and controlled implementation in environments built on Fortinet technologies.

What organizations should avoid

Post-quantum readiness does not require panic or the immediate replacement of every algorithm.

Organizations should avoid:

• buying solutions solely because they are labelled “quantum-safe”
• replacing algorithms without interoperability and performance testing
• assuming that one technology solves every cryptographic dependency
• overlooking digital signatures and authentication
• waiting until a practical quantum attack becomes available
• treating the transition as a purely technical task

Every change should be based on the actual environment, the sensitivity period of the data, and verifiable vendor support.

The DIAMATIX perspective

The main question is not the exact date on which a quantum computer capable of compromising widely used public-key cryptography will appear.

The more important questions are:

• Does the organization know where it uses cryptography?
• Which data must remain protected for 5, 10, or more years?
• Which systems depend on mechanisms that will need to be replaced?
• Do key vendors have credible migration plans?
• Does the architecture allow controlled changes to algorithms and certificates?

DIAMATIX views post-quantum readiness as part of long-term cyber risk management.

The first step is visibility. This is followed by prioritization, vendor assessment, testing, and the gradual development of crypto-agility.

Preparation does not begin with rushed replacement. It begins with an inventory and a realistic plan.

Conclusion

The transition to post-quantum cryptography will likely take years. It will affect applications, networks, certificates, devices, vendors, and risk-management processes.

The published NIST standards, the European roadmap, and the specific deadlines for certain U.S. federal systems show that the topic is already part of real technology and governance planning.

For most organizations, there is no reason for an immediate large-scale migration. There is sufficient reason to begin with a cryptographic inventory, an assessment of long-lived sensitive data, and discussions with key vendors.

Post-quantum resilience is built gradually. With clear ownership, measurable risk, and an architecture designed for change.

Sources

• NIST. First Three Finalized Post-Quantum Cryptography Standards.
• NIST CSRC. FIPS 203, FIPS 204 and FIPS 205.
• European Commission. Recommendation on a Coordinated Implementation Roadmap for the Transition to Post-Quantum Cryptography.
• NIS Cooperation Group. Coordinated Implementation Roadmap for the Transition to Post-Quantum Cryptography.
• The White House. Securing the Nation Against Advanced Cryptographic Attacks.
• Fortinet. From Awareness to Action: Helping Organizations Prepare for Post-Quantum Cryptography.
• Fortinet Product Documentation. Post-Quantum Cryptography for IPsec, TLS and FortiOS.