Learning path
Quantum-safe security
“I work in security and I need to know what quantum means for cryptography.”
Security engineers, cryptographers and IT leads planning a migration. Assumes you know what RSA and a key exchange are.
3 milestones · 11 steps · 115 minutes of reading, plus hands-on time
By the end, you will be able to
- Explain exactly which cryptography Shor's algorithm breaks, and which it does not
- Put Grover's effect on symmetric keys in the right proportion
- Describe how quantum key distribution detects an eavesdropper, and its practical limits
- Plan a post-quantum migration using the standardised algorithms
Milestone 1: Just enough quantum
3 stepsYou have the minimum physics to follow the threat model precisely.
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- LessonBeginner10 minSuperposition & Measurement
Why a quantum computer is not just trying every key at once.
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Milestone 2: The threat
4 stepsYou know what a large quantum computer breaks, and roughly what it would take.
- LessonAdvanced18 minShor's Algorithm
Factoring and discrete logs: the end of RSA and elliptic curves.
Auto-tracks - VisualizationAdvancedShor's Algorithm: Period Finding
Period finding, the core of the attack, running in front of you.
- LessonAdvanced15 minGrover's Search
The symmetric-key story: a quadratic speedup, answered by longer keys.
Auto-tracks - LessonAdvanced20 minQuantum Error Correction
Why a cryptographically relevant machine is a fault-tolerance problem.
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Milestone 3: The defences
4 stepsYou can compare the quantum and post-quantum answers and choose between them.
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- VisualizationIntermediateQuantum Key Distribution
Run BB84 with an eavesdropper and watch the error rate give her away.
- VisualizationIntermediateThe Bell Test
The device-independent argument behind entanglement-based QKD.
- LessonAdvanced18 minPost-Quantum Cryptography
Lattice-based and hash-based schemes, and how to migrate to them.
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Progress is stored in this browser only. Lessons tick themselves when you finish them and challenges when you solve them; everything else you tick yourself, because opening a page is not the same as understanding it.
After this path
- Inventory where your organisation uses RSA and elliptic-curve keys — that list is the start of every migration plan.
- Read the NIST post-quantum standards (FIPS 203, 204 and 205) with the background to follow them.