K2 Components, split knowledge and dual control
Needs: Supporter
How custodians create, exchange and verify keys without anyone knowing the whole key.
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What this module covers
You will be able to
- Generate, combine and verify components
- Run a key ceremony checklist
- Explain why component order does not matter and a wrong component does
The lesson
- Why it matters
- The concept
- Step by step: a ZMK ceremony
- In the real world
- Common mistakes
- What to test
In the module
- The lesson, with diagrams, common mistakes and what to test
- A worked example you can change: A key ceremony in numbers
- Practice: 2 kinds of generated exercise, each with a step-by-step solution
- A quiz of 8 questions
Key terms
- Dual control
- A sensitive step needs at least two authorised people acting together, such as loading the components of a master key.
- Key ceremony
- A scripted, witnessed and logged session in which keys are generated, loaded or exchanged under dual control.
- Key component
- One of the parts that are XORed together to form a key. Each custodian holds one and none reveals anything about the key.
- Key custodian
- A named person entrusted with one key component, who keeps it in a sealed envelope or smart card and enters it in key ceremonies.
- Key loading device (KLD)
- A secure device that carries keys to terminals or HSMs and loads them.
- Secure cryptographic device (SCD)
- Any device approved to hold keys in the clear: HSMs, PIN pads, key loaders.
- Split knowledge
- No single person knows the whole key: each knows only a component.
- Tamper-evident bag
- A numbered bag that shows any attempt to open it, used to store key components and devices.
The lesson, worked example, practice and quiz open with a supporter pass, which you can try free for 7 days.