Chapter 38 — Web3, blockchain and cryptoasset security: validation
Lesson map
Lesson 38 published. Map, example, EX112.
flowchart TD
N0["Learning outcomes"]
N1["38.1 Verification versus validation"]
N2["38.2 External review"]
N3["38.3 Responding to findings"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4
N4 --> EX["Worked example"]
EX --> Q["Exercise EX112"]
Logical drawing
flowchart LR
N0["Learning outcomes"]
N1["38.1 Verification versus validation"]
N2["38.2 External review"]
N3["38.3 Responding to findings"]
N4["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> Q["EX112"]
[Learning outcomes]
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v
[38.1 Verification versus validation]
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v
[38.2 External review]
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v
[38.3 Responding to findings]
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v
[Synthesis]
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v
[Worked example] --> [Exercise EX112]
Learning outcomes
You will (1) validate the system against stakeholder needs; (2) commission an external review; (3) respond to findings.
38.1 Verification versus validation
Verification asks whether the system was built right, according to specifications; validation asks whether the right system was built, meeting stakeholders' real needs. Jonas validates by observing members using the app, interviewing the board and checking with the utility that redemption reports work for billing. He finds members confused by pending balances despite the earlier fix, and that some elderly members prefer monthly paper statements. Validation finds needs that specifications missed. He records each validation finding with its source and agrees changes with the board, such as offering monthly paper statements.
38.2 External review
The cooperative commissions an external security review of the contracts against the EthTrust Security Levels at level M, using the review pack. Reviewers report no high-severity issues, two medium issues and four informational notes. One medium issue concerns a missing event when the minting cap is changed, which would make monitoring harder; the other concerns rounding in fee calculation that slightly favours the sender. Jonas records each finding with its requirement and planned fix. He also confirms which parts of the system were outside the review's scope.
38.3 Responding to findings
Both medium issues are fixed, retested and confirmed by the reviewers. The rounding fix follows EthTrust guidance that rounding must not create value for the initiator. Informational notes are either adopted or recorded with reasons for not adopting. Jonas publishes a summary of the review and responses to members in plain language. Responding transparently to review findings builds trust and demonstrates that the cooperative takes security seriously. Members are invited to ask questions at the next general meeting, and the summary is kept with the review report so future reviewers can see how earlier findings were handled.
Worked example
Validation reveals confusion about pending balances and demand for paper statements; an EthTrust level M review finds two medium issues, both fixed and confirmed.
Synthetic case. Reviews, findings and members are synthetic; EEA EthTrust is a real source.
Errors and limits
Treating a passed external review as proof of security ignores its stated limits.
Exercises
- EX112 — Validation question. What does validation ask? Rubric: 3 = whether the right system was built;; 2 = needs;; 1 = built right;; 0 = none.
- EX113 — Review result. What did the external review find? Rubric: 3 = no high, two medium, four informational;; 2 = two medium;; 1 = vague;; 0 = none.
- EX114 — Rounding fix basis. What guidance did the rounding fix follow? Rubric: 3 = rounding must not create value for the initiator;; 2 = EthTrust rounding;; 1 = vague;; 0 = none.
Synthesis
Validation with stakeholders and transparent response to external review confirm the system meets real needs.
Continue studying — chapter 38 of 50
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