📰 Originally published on Securityelites — AI Red Team Education — the canonical, fully-updated version of this article.
Have you ever thought of what will happen to cryptography(your passwords, encryptions, rsa tokens, auth tokens etc.) when Quantum Computing comes into hands of state actors? My plain-English guide for security teams on what post-quantum cryptography means, what you need to do now, and the NIST standards that define the path forward.
What You’ll Learn
Why quantum computers threaten current encryption
What “harvest now, decrypt later” attacks are and why they’re happening now
The NIST post-quantum cryptography standards and what they mean
How to assess your organisation’s quantum risk exposure
The practical migration steps security teams need to start now
⏱️ 12 min read ### Post-Quantum Cryptography — Security Team Guide 2026 1. Why Quantum Computers Threaten Current Encryption 2. Harvest Now, Decrypt Later — The Immediate Threat 3. NIST PQC Standards — What Got Standardised 4. Assessing Your Quantum Risk 5. The Migration Roadmap Post-quantum cryptography is a Gartner Top Cybersecurity Trend for 2026 and the subject of active government mandates globally. For the AI acceleration of this threat, see the Nation-State AI Cyberwarfare guide. The broader cryptography fundamentals are in the Ethical Hacking series.
Why Quantum Computers Threaten Current Encryption
My plain-English explanation for security teams who haven’t followed the quantum cryptography narrative closely — and there’s no shame in that, it’s been a niche topic until recently: the threat isn’t that quantum computers will brute-force your encryption password. It’s that they can efficiently solve the mathematical problems that make current public-key encryption secure. RSA encryption is secure today because factoring a large number into its prime factors is computationally infeasible for classical computers. A sufficiently powerful quantum computer running Shor’s algorithm can solve that factoring problem efficiently in polynomial time — making RSA breakable.
QUANTUM THREAT TO CRYPTOGRAPHY — PLAIN ENGLISHCopy
Vulnerable algorithms (quantum-breakable)
RSA: broken by Shor’s algorithm (factoring large integers)
ECC (Elliptic Curve): broken by Shor’s algorithm (discrete logarithm)
DH (Diffie-Hellman): broken by Shor’s algorithm
Used in: TLS/HTTPS, SSH, VPN, email encryption, certificate infrastructure
More resistant algorithms
AES-256: requires Grover’s algorithm → doubles key length needed (still 128-bit security with 256-bit key)
SHA-3: resistant to known quantum attacks
Symmetric encryption generally: weakened by Grover’s algorithm but not broken — key length doubling mitigates this
The timeline
Current quantum computers: too small and error-prone to break real encryption
Expert estimates: 10–15 years before cryptographically relevant quantum computers exist
Critical point: Palo Alto notes “AI has dramatically accelerated this timeline”
For long-lived data: the threat is now — not in 10 years
Harvest Now, Decrypt Later — The Immediate Threat
The reason I tell security teams to act now rather than waiting for quantum computers to arrive: harvest now, decrypt later (HNDL) attacks are already happening. State actors are collecting encrypted communications today — TLS sessions, VPN traffic, encrypted files — storing them, and waiting until quantum computers are powerful enough to decrypt them. My firm assessment: any organisation handling data that needs to remain confidential for more than a decade should treat HNDL as an active, present threat, not a future one.
HARVEST NOW DECRYPT LATER — THE THREAT MODELCopy
Who is doing this
Nation-state actors with long-term intelligence objectives
Primary targets: government comms, defence contractors, critical infrastructure, pharma R&D
US CISA confirmed: multiple nation-states are actively conducting HNDL collection
What they’re harvesting
TLS/HTTPS traffic captured at internet exchange points or via network taps
Encrypted files exfiltrated from breached organisations
VPN session captures from government and corporate networks
Encrypted email archives
AI’s role in accelerating the threat
AI accelerates quantum computer development timelines (ML for error correction)
AI optimises collection strategies — which traffic to prioritise harvesting
Palo Alto: AI has “dramatically accelerated” the timeline for this threat
Your data that’s at risk
Any encrypted data that needs to remain confidential beyond 2035
Trade secrets, patents, long-term contracts, medical records, state secrets
Authentication credentials and keys used to protect long-lived assets
NIST PQC Standards — What Got Standardised
NIST finalised its first post-quantum cryptography standards in August 2024 after a multi-year evaluation process. My summary of what was standardised and what it practically means for security teams and organisations beginning migration planning.
NIST PQC STANDARDS — FINALISED AUGUST 2024Copy
FIPS 203 — ML-KEM (Kyber)
Purpose: key encapsulation mechanism — replaces RSA/ECC for key exchange
Use cases: TLS handshake, SSH key exchange, VPN connections
Status: finalised — primary recommendation for key exchange
FIPS 204 — ML-DSA (Dilithium)
Purpose: digital signatures — replaces RSA/ECDSA for signing
Use cases: code signing, certificate signing, document signing
Status: finalised
FIPS 205 — SLH-DSA (SPHINCS+)
Purpose: stateless hash-based signatures — backup signing algorithm
Strength: based on different mathematical assumptions than ML-DSA
Status: finalised
What this means for your organisation
Standards are done — vendors are now implementing them in products and libraries
Migration target: FIPS 203 for key exchange, FIPS 204 for signatures
Hybrid approach: many vendors deploying classical + PQC simultaneously during transition
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