Preparing for the Post-Quantum Era:
In 2026, quantum computing is no longer a distant concept, but an active security risk with grave implications for federal agencies, defense contractors, and critical infrastructure. As quantum capabilities accelerate across the globe, the U.S government continues to push towards post-quantum cryptography (PQC), secure communications, and crypto-agile architecture. Today’s threat is very straightforward; once quantum systems reach scale, today’s most common encryption methods (RSA, ECC, DSA) will become breakable.
This shift is causing NIST, the Pentagon, and the White House AI Action Plan to frame quantum security as a strategic priority. Agencies that begin preparing now will avoid costly scenarios in the future and protect long-lived data from “harvest now, decrypt later” attacks already taking place.
What is Post-Quantum Cryptography?
Post-quantum cryptography refers to cryptographic algorithms that are designed to withstand attacks from large-scale quantum computers. Unlike traditional encryption, which is reliant on the difficulty of factoring large prime numbers, PQC uses mathematical problems that quantum computers cannot efficiently solve.
NIST, the National Institute of Standards and Technology, has already begun implementing its PQC plans and has built out its foundation on five major cryptography families.
- Lattice-Based Cryptography: Uses geometric problems in high-dimensional lattices to provide PQC encryption and signatures
- Multivariate Cryptography: Builds security on the difficulty of solving large systems of nonlinear polynomial equations over finite fields
- Hash-Based Signatures: Generate digital signatures using one-way hash functions
- Code-Based Cryptography: Reliant on the hardness of decoding ECC
- Isogeny-Based Cryptography: Uses the complexity of finding paths between elliptic curves (Isogenies) to create lightweight, quantum-resistant key exchanges
These approaches are designed to resist Shor’s Algorithm, the quantum algorithm that can break RSA and ECC by rapidly solving integer factorization and discrete logarithm problems.
“Harvest Now, Decrypt Later”
To prepare for post-quantum cryptography, agencies are collecting encrypted traffic, files, and backups today, expecting that quantum computers will be able to instantly detect the information. The “Harvest Now, Decrypt Later” model is already active, targeting long-lived data like PII, legal records, government communications, and intellectual property. As soon as quantum systems mature, attacks will be able to retroactively decrypt years of stolen ciphertext, which is why NIST, CISA, and NSA are stressing the importance of PQC.
The HNDL attack chain looks like this:
- Steal encrypted data
- Store it for years
- Wait for quantum advancements
- Decrypt using quantum algorithms
- Exploit the plaintext
Why Agencies Must Modernize VPNs & Firewalls:
Preparing for post-quantum security is about more than just adopting new algorithms; PQC requires modernizing the infrastructure that protects encrypted traffic. VPNs, firewalls, and secure gateways must be capable of supporting hybrid cryptography, updated protocols, and crypto-agile configurations. By not upgrading these systems, agencies increase their risk of creating bottlenecks where quantum-vulnerable encryption remains in place after PQC standards are available. Modernizing network security ensures that encrypted communications, remote access, and inter-agency data flows remain protected as quantum capabilities evolve.
Secure VPN Requirements for Post-Quantum
A quantum-ready VPN needs to support hybrid cryptography, enabling classical and post-quantum algorithms to operate together during the transition period. Agencies should look for VPNs that offer multi-OS compatibility, high-speed throughput for encrypted workloads, and optional DDoS mitigation to protect against volumetric attacks. Enterprise-grade infrastructure and support for NIST PQC standards are vital as vendors begin to roll out ML-KEM and ML-DSA-based protocols.
A quantum-ready VPN should include:
- Support for hybrid cryptography (classical + PQC)
- Multi-OS computability
- High-speed throughput for encrypted workloads
- Optional DDoS mitigation and enterprise-grade infrastructure
Firewalls in a Post-Quantum World
Firewalls will be required to handle PQC-safe protocols, updated packet inspection methods, and crypto-agile rule sets. Agencies should make sure their firewalls support granular IP and domain filtering, port-based traffic control, keyword scanning, and continuous rule updates to adapt to emerging threats. Logging and auditability remain critical for compliance, while support for PQC-compatible TLS and VPN protocols will become mandatory as NIST standards are adopted.
Key configuration areas include:
- IP address and domain filtering
- Port-based traffic control
- Keyword scanning and threat flagging
- Continuous rule updates
- Logging and auditability
- Support for PQC-compliant TLS and VPN protocols
NIST Post-Quantum Standards to Know
NIST has selected its core set of algorithms to define a federal cryptography standard for the next decade. Follow along with our guide for which NIST-approved algorithms agencies should implement.
- FIPS 203 – ML – KEM: Provides quantum-resistant key establishment
- FIPS 204 – ML – DSA: Delivers secure digital signatures for authentication
- FIPS 205 – SLH – DSA: Offers hash-based signatures as a highly secure backup option
- FIPS 206 – FALCON: High-performance signatures (in development)
Agencies should highlight the importance of tracking vendor adoptions now, before they replace RSA, ECC, and DSA across federal systems.
Quantum Readiness Roadmap for Agencies
To ensure a smooth transition to post-quantum cryptography, it is key to create a structured roadmap. The first step is to inventory all cryptographic assets, including TLS, VPNs, SSH, and application-level encryption. Agencies will then identify long-lived and high-value data, which will remain sensitive even if decrypted years in the future. Prioritizing systems vulnerable to RSA and ECC compromise enables targeted modernization.
Follow along with our roadmap for PQC to help guide your agency during this transition.
- Inventory all cryptographic assets
- Identify long-lived and high-value data
- Prioritize systems vulnerable to RSA/ECC compromise
- Plan hybrid cryptography rollouts
- Build crypto-agility into new architectures
- Coordinate with vendors and integrators
- Monitor NIST and NSA guidance continuously
(This roadmap aligns with federal PQC mandates and industry best practices)
Quantum-Readiness Checklist
Is your agency quantum-ready? Read our quantum readiness checklist to help evaluate your preparedness for quantum.
- Have we identified all systems using RSA, ECC, or DSA?
- Do we know which data must remain secure for 10+ years
- Are our VPNS and firewalls ready for hybrid PQC?
- Do we have a crypto-agility plan for future algorithm changes?
- Are we tracking NIST PQC standards and vendor roadmaps
- Have we evaluated quantum-resistant VPN options?
- Are we monitoring HNDL risks in our environment?
- Do we have a migration plan for TLS, SSH, and IPsec?
Listen to our quantum expert, Joey Swartz’s new video to learn more about why taking the first steps now in quantum computing is essential to your agency’s overall success.
Preparing for PQC, Final Steps:
Quantum computing will fundamentally reshape cybersecurity, and the transition to PQC has already begun. Agencies that are acting now will avoid costly disruptions, protect long-lived data, and stay aligned with federal requirements. ATP Gov partners with leading technology providers to help organizations modernize VPNs, firewalls, and cryptographic infrastructure for the post-quantum era, ensuring mission-critical systems remain secure today and tomorrow.
If you have any questions or would like to schedule a consultation, please reach out to us via our contact us form and speak with an expert.