Chapter 1 — Advanced security decision-making
Lesson map
Lesson 01 published. Map, example, EX001.
flowchart TD
N0["Learning outcomes"]
N1["1.1 The case and the decision"]
N2["1.2 Criteria and uncertainty"]
N3["1.3 Recording decisions for review"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4
N4 --> EX["Worked example"]
EX --> Q["Exercise EX001"]
Logical drawing
flowchart LR
N0["Learning outcomes"]
N1["1.1 The case and the decision"]
N2["1.2 Criteria and uncertainty"]
N3["1.3 Recording decisions for review"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX001"]
[Learning outcomes]
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[1.1 The case and the decision]
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[1.2 Criteria and uncertainty]
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v
[1.3 Recording decisions for review]
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v
[Synthesis]
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v
[Worked example] --> [Exercise EX001]
Learning outcomes
You will (1) frame security decisions under uncertainty; (2) weigh options with explicit criteria; (3) record decisions for later review.
1.1 The case and the decision
Nadia Rahman is a risk manager studying part-time for a postgraduate diploma at the fictional Westbrook Institute, supervised by Professor Mei Tanaka. Her employer, the fictional Harbourside Regional Credit Union, is considering a pilot with two partner credit unions to settle inter-bank transfers as tokenised deposits on a shared permissioned ledger. All people, organisations and numbers here are synthetic. Nadia's first task is to frame the decision clearly: whether to join the pilot, under what conditions, and with what safeguards. A well-framed decision names the options, the uncertainties and the people who will bear the consequences.
1.2 Criteria and uncertainty
Nadia lists criteria with the credit union's risk committee: settlement speed, operational resilience, control over keys, regulatory acceptability, cost and reversibility of the decision. Several are uncertain: the pilot ledger's resilience is unproven and regulators have not yet commented. She represents uncertainty with ranges rather than single numbers and identifies which uncertainties could change the decision. Reversibility receives a high weight because a pilot that cannot be exited cleanly would turn a small experiment into a lasting dependency. Making criteria explicit lets the committee disagree productively about weights rather than talking past each other.
1.3 Recording decisions for review
Nadia drafts a decision record: join the pilot with a capped exposure of 2 million in synthetic settlement value, a six-month term, an exit plan and named conditions for stopping early. The record states the assumptions, the evidence available and what new evidence would change the decision. Professor Tanaka notes that decisions under uncertainty should be judged by the quality of their reasoning, not only by outcomes, since good decisions can turn out badly by chance. Recording reasoning allows the committee to learn honestly when it reviews the pilot later.
Worked example
Nadia frames the pilot decision with six criteria, high weight on reversibility, and records a capped six-month entry with stop conditions.
Synthetic case. Nadia Rahman, Professor Mei Tanaka, Westbrook Institute, Harbourside Regional Credit Union and all figures are synthetic.
Errors and limits
Judging a decision only by its outcome confuses bad luck with bad reasoning.
Exercises
- EX001 — Pilot purpose. What would the pilot settle on a shared ledger? Rubric: 3 = inter-bank transfers as tokenised deposits;; 2 = tokenised deposits;; 1 = retail payments;; 0 = none.
- EX002 — Weighted criterion. Why does reversibility get a high weight? Rubric: 3 = an unexitable pilot becomes a lasting dependency;; 2 = exit matters;; 1 = it is cheap;; 0 = none.
- EX003 — Exposure cap. What exposure cap does the record set? Rubric: 3 = 2 million in synthetic settlement value;; 2 = 2 million;; 1 = unlimited;; 0 = none.
- EX004 — Pilot term. How long is the proposed term? Rubric: 3 = six months;; 2 = 6 months;; 1 = two years;; 0 = none.
- EX005 — Judging decisions. How should decisions under uncertainty be judged? Rubric: 3 = by the quality of reasoning, not only outcomes;; 2 = reasoning;; 1 = outcomes only;; 0 = none.
Synthesis
Explicit criteria, honest uncertainty and recorded reasoning support sound security decisions.