Chapter 8 — Web3, blockchain and cryptoasset security: difficult cases
Lesson map
Lesson 08 published. Map, example, EX036.
flowchart TD
N0["Learning outcomes"]
N1["8.1 An ambiguous alert"]
N2["8.2 Deciding under time pressure"]
N3["8.3 Learning from near misses"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4
N4 --> EX["Worked example"]
EX --> Q["Exercise EX036"]
Logical drawing
flowchart LR
N0["Learning outcomes"]
N1["8.1 An ambiguous alert"]
N2["8.2 Deciding under time pressure"]
N3["8.3 Learning from near misses"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX036"]
[Learning outcomes]
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v
[8.1 An ambiguous alert]
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v
[8.2 Deciding under time pressure]
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v
[8.3 Learning from near misses]
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v
[Synthesis]
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v
[Worked example] --> [Exercise EX036]
Learning outcomes
You will (1) analyse ambiguous situations; (2) decide under time pressure; (3) learn from near misses.
8.1 An ambiguous alert
In a synthetic scenario, monitoring shows a partner's validator signing blocks with a delay of several seconds and a small settlement batch appears twice in the pending queue. It could be a network fault, a misconfigured retry or something more serious. Nadia's team must decide whether to pause. She uses the joint procedure: gather facts quickly, contact the partner's operations lead, check whether the duplicate would pass the batch summary's repeat check, and decide within thirty minutes. Ambiguous situations are where procedures matter most, because they replace panic with a sequence of known steps.
8.2 Deciding under time pressure
Within twenty minutes the partner confirms a network fault causing retries, and the batch summary flags the duplicate, so reviewers reject it. The team decides not to pause, because the control worked and pausing would delay all settlement. Nadia records the decision, the facts known at the time and the reasoning. Under time pressure, decisions should be proportionate: pausing is a strong action with real costs. She notes that if the duplicate had not been flagged, or the partner had been unreachable, the procedure would have favoured pausing until facts were clearer.
8.3 Learning from near misses
The near miss reveals that the partner's retry setting could produce duplicates, and that only the batch summary stopped one reaching signing. Nadia leads a blameless review. Improvements include a contract-level check rejecting any transfer identifier already settled, and alignment of retry settings across partners. Near misses are valuable because they reveal weaknesses without causing harm. She reports the near miss to the joint operations group and the risk committee, which reinforces a culture where people report problems early instead of hiding them out of embarrassment.
Worked example
A duplicate from a partner's retry is caught by the batch summary, the team decides not to pause, and a contract-level duplicate check is added.
Synthetic case. The scenario and response are synthetic.
Errors and limits
Pausing reflexively on every ambiguous alert imposes costs that a working control may have made unnecessary.
Exercises
- EX036 — Decision deadline. Within what time must the team decide? Rubric: 3 = thirty minutes;; 2 = 30 minutes;; 1 = one day;; 0 = none.
- EX037 — Fault cause. What caused the duplicate in the scenario? Rubric: 3 = a network fault causing retries;; 2 = retries;; 1 = theft;; 0 = none.
- EX038 — Pause decision. Why does the team not pause? Rubric: 3 = the control worked and pausing would delay everything;; 2 = proportionality;; 1 = forgot;; 0 = none.
- EX039 — Contract improvement. What contract improvement follows? Rubric: 3 = reject any transfer identifier already settled;; 2 = duplicate check;; 1 = vague;; 0 = none.
- EX040 — Near-miss value. Why are near misses valuable? Rubric: 3 = they reveal weaknesses without harm;; 2 = learning;; 1 = they are not;; 0 = none.
Synthesis
Clear procedures, proportionate decisions and near-miss learning handle difficult cases well.
Continue studying — chapter 08 of 12
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