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Quantum Defense

A free course · 18 lessons · no sign-up

Post-quantum cryptography, from first principles.

How quantum computers threaten the encryption we use today, and what replaces it. Start with no math at all, or skip ahead to the internals of ML-KEM. Every lesson has something you can run, break or forge in your browser.

A course by Kyeson Blake Utley

Start with lesson 1See the route
Fig. 0The closest-vector problem
Move the pointer (or tap) anywhere on the grid. The solid line finds the nearest lattice point. Simple rounding with a short, nearly square basis finds it about nine times in ten. Switch to a long, skewed basis for the same lattice and rounding is right less than one time in five. In hundreds of dimensions, finding the nearest point without a good basis is believed to be hard even for quantum computers. FN-DSA (Falcon) is built on exactly this gap, and ML-KEM on a close cousin of it, Learning With Errors.

Three parts. Read them in order, or don’t.

Part I assumes nothing. Part II is for the people who will run a migration. Part III is for the people who will implement one.

I

No math required · 6 lessons · 82 min

Foundations

For curious beginners, students and executives. What cryptography does, what a quantum computer really is, and why everyone is suddenly in a hurry.

  1. What cryptography actually does
  2. Public keys, private keys and the locked mailbox
  3. What a quantum computer is (and isn't)
  4. Shor's algorithm: why RSA and elliptic curves fall
  5. Grover's algorithm: why AES survives
  6. Harvest now, decrypt later
 II

Some tech background · 6 lessons · 83 min

Practitioner

For IT, security, compliance and product people. The new NIST standards, the government deadlines, and how a real migration runs from inventory to rollout.

  1. Meet the new standards: ML-KEM, ML-DSA and friends
  2. Hybrid key exchange: post-quantum TLS today
  3. The deadlines: who requires what, and when
  4. Cryptographic inventory: find it before you fix it
  5. Crypto-agility: build to swap
  6. Migrating certificates, code signing and firmware
 III

Math and code · 6 lessons · 107 min

Engineer

For developers and engineers. Lattices and Learning With Errors, ML-KEM from the inside, hash-based signatures built from scratch, and the implementation bugs that bite.

  1. Lattices and Learning With Errors
  2. Inside ML-KEM
  3. Lamport signatures: hash-based signing from scratch
  4. Winternitz chains and Merkle trees
  5. Implementation pitfalls: timing, state and randomness
  6. Cryptocurrency in a post-quantum world

How each lesson works

01Read

A plain-English summary up top, then the real explanation. Optional “go deeper” boxes hold the math.

02Run

Factor a number, step through Grover’s algorithm, forge a reused signature. It all runs locally.

03Check

Two quick checks along the way and six questions at the end. Five right marks the lesson done.

04Finish

The final exam draws 20 questions from the whole course. Pass it and print a certificate.

Try one

This one is from lesson 1. The other 18 are in the playground.

Why bother now?

Anything encrypted today with RSA or elliptic curves can be recorded now and decrypted later, once a large enough quantum computer exists. That’s why governments aren’t waiting. NIST published the first post-quantum standards in August 2024. Its draft transition plan deprecates RSA-2048-class algorithms after 2030 and disallows them after 2035, and the NSA wants national security systems moved to quantum-resistant algorithms by 2035.

Every deadline on one timeline →

Kyeson Blake Utley, creator of the Quantum Defense curriculum

About the author

Kyeson Blake Utley

Kyeson Blake Utley created this course to make post-quantum cryptography understandable at every level, from the boardroom to the codebase. Kyeson is a Texas security engineer and the founder of GhostKey Development, a Texas security engineering firm focused on post-quantum migration, cryptocurrency systems and penetration testing.

More about the course and its author →

Questions people ask

Is it really free?

Yes. Every lesson, interactive, quiz and the final exam are free, with no account and no email signup. Your progress is stored only in your own browser.

Do I need to know math?

Not for Part I. Foundations uses analogies and interactives instead of equations. Part II assumes you know what TLS and certificates are. Part III assumes modular arithmetic and some code.

Who created this?

The curriculum was created by Kyeson Blake Utley, a Texas security engineer who works on post-quantum migration and cryptocurrency security. More about the curriculum and its creator.

Is the certificate accredited?

No. It's a printable record that you passed the final exam, which is useful for your own records or a manager, but it isn't a professional certification.

How do you keep it accurate?

Dates, sizes and deadlines are taken from primary sources: NIST FIPS 203–205, NSA's CNSA 2.0, NIST IR 8547, the UK NCSC and the EU roadmap. Every lesson lists its sources. Spot an error? Tell us.

When will quantum computers break RSA?

Nobody knows, and anyone who gives you an exact year is guessing. What is known is that governments have set migration deadlines in the early-to-mid 2030s, and that data stolen today can be decrypted later. Lesson 6 explains why that matters now.