The shared Wi-Fi secret stays unwritten

Lesson map

Lesson 15. Map, example, EX061.

flowchart TD
  A["A shared password keeps neighbours out"] --> B["Users on the network are not protected from each other"]
  B --> C{"Is the password printed?"}
  C -->|No| D["State the limit without the secret"]
  C -->|Yes| E["Writing it spreads a secret"]

The limit can be taught without the secret, and the council equipment stays out of scope.

Logical drawing

public Wi-Fi
    shared password
    not printed
    blocks casual neighbours
    does not separate users
out of scope
    council Wi-Fi equipment
    scanning
    the kiosk stays uncrashed because no scan is recorded

Learning outcomes

After this chapter, you should be able to:

1. State both the reach and the limit of the shared password.
2. Leave that password unwritten.
3. Leave scanning, the council equipment, and a kiosk crash out of the file.

15.1 The limit is public. The secret is not.

Public Wi-Fi uses a shared password. Chapter 3 says it keeps out casual neighbours and does not protect people on the network from one another. The password itself never appears. The signed note forbids scanning and forbids touching the council's Wi-Fi equipment. The old self-service kiosk is the fragile device an unapproved scan might disrupt, and Inês stopped the scan before it happened, so the file contains no crash. A classmate who prints the shared password "so staff can see the risk" puts a secret into a note, which the four rules forbid. A classmate who scans "only the library side" still does the action the note refused. Leo can teach the limit with the sentence already written. He does not need the secret, a scan, or a damaged kiosk to make the point.

15.2 Worked example

Lesson table; scroll horizontally to read all columns →

Synthetic case. No Wi-Fi password and no crash log are created.

Errors and limits

Teaching the limit without the secret does not make the shared password stronger than chapter 3 said.

Apply

• EX061 — Write the password? The shared Wi-Fi password keeps casual neighbours out and does not protect users from each other. Scanning and the council's equipment are outside the note. What do you add to the summary?
  Show marking criteria

  Rubric: 3 = state the reach and the limit; do not write the password; do not scan; do not touch the council equipment; the kiosk crash is not in the file;; 2 = the secret stays unwritten and the scan stays undone;; 1 = one limit;; 0 = none.