One day, a large enough quantum computer will solve the mathematical puzzles that today protect nearly every login, payment, message, and software update on earth. The public-key cryptography that secures the internet — RSA, elliptic-curve, Diffie–Hellman — was chosen precisely because ordinary computers cannot break it in any practical time. Quantum computers change that assumption for one specific, load-bearing family of algorithms. This series explains the whole story from first principles and then turns it into action: a structured, vendor-neutral post-quantum readiness assessment grounded in the finalised NIST standards (FIPS 203, 204, 205) and the published transition guidance, with Microsoft’s already-shipping support used as the worked example.

Every article stands on its own, is written so a newcomer can follow it while a practitioner still finds it useful, and carries a “new here / know the basics” signpost so you can read at your own level. The series is organised as six parts — a deliberate climb from a bedtime-story explanation to an enterprise migration roadmap.

What we mean by “quantum-safe”

You’ll meet several near-synonyms in this field, and they all point at the same goal. Quantum-safe, post-quantum (PQC, short for post-quantum cryptography), and quantum-resistant all describe cryptography that stays secure even against a large quantum computer. They’re used interchangeably — the difference is emphasis, not meaning.

This guide leads with quantum-safe deliberately. It’s the plain-language, outcome-focused term: the point isn’t the era (“post-quantum”) or the maths (“the algorithms”) — it’s the result you want, systems that are safe against a quantum attack. “Post-quantum” is the more formal name carried by the NIST standards (FIPS 203/204/205), so both terms appear throughout; now you know they mean the same thing.

★ New to quantum computing itself? You can jump straight to Classical vs Quantum Computers for the machine, then Qubits, Superposition & Entanglement — and pick up the cryptography basics anytime.

⚡ Securing AI workloads? The series closes with Quantum-Safe AI — why your training data, model weights, and agent-to-agent trust are exactly what quantum threatens, and how post-quantum readiness is AI security.

Foundations — start here, no knowledge assumed

What secrets, keys, encryption, and quantum computers actually are — in plain language, with pictures.

The Threat — why this is urgent now

Why the danger is present-tense, and exactly which parts of the internet’s security break.

The New Rulebook — the standards that replace them

The finalised NIST algorithms that replace the broken ones — what they are and how they work.

The Readiness Assessment — the centrepiece

The structured method to find, prioritise, and score your organisation’s cryptographic exposure.

Migration & Governance — getting it done

Turning the plan into action, on real platforms, reported to the people who fund it.

The AI Frontier — where this lands for AI-first teams

Why post-quantum readiness is AI security: long-lived data, agent trust, model provenance, and crypto-agility.

About this series

This series is vendor-neutral. The cryptography, the threat, and the readiness method are grounded in public, widely-recognised sources: the finalised NIST standards FIPS 203 (ML-KEM), FIPS 204 (ML-DSA) and FIPS 205 (SLH-DSA); NIST’s transition report IR 8547; the NSA’s CNSA 2.0 suite; and CISA/NSA quantum-readiness guidance. Where a product is named — most often Microsoft’s, because it is already shipping post-quantum support in SymCrypt, Windows CNG, Active Directory Certificate Services, Schannel/TLS, and .NET 10 — it is used as a concrete worked example of a category, not an endorsement, and the same reasoning applies to any comparable platform.

It is a companion to the security-engineering field guides elsewhere on this site: where the Anti-Patterns Catalogue asks “what design mistakes make an agent unsafe?” and Supply-Chain Trust asks “how do I trust code I bring in?”, this one asks a longer-horizon question: “will the cryptography underneath all of it still be standing in ten years — and what do I do now if not?”

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