Security, Usability & Functionality

Lesson plan

Level

Beginner

Time

About 75 minutes; the steps below add up to 75

Learners meet a fire door wedged open with a chair and work out, before anything is named, that a measure must also be usable and do its job. The three questions are then named and applied. Every place where intuition misleads opens with a prediction: whether security must make things harder, monthly password changes, a folder staff cannot open, a flood of alerts, and the second sign-in proof for a screen-reader user. The diagram of the restriction with its two routes follows the story it summarises. The habit to build: judge a control by what it makes people actually do, and look for a design that keeps the protection with less difficulty.

Objectives

• Judge a security measure by three questions at once: protection, ease of use and whether the work can still be done
• Show that a restrictive rule can make security worse, by following what people actually do
• Explain why accessibility means an equally safe route, not a weaker one
• Recognise a workaround as evidence about a control’s design
• Choose second sign-in proofs for different people, and say why one answer does not suit everyone

Before the lesson

• Open this page on your own screen and use “Open the lesson window” to open the lesson in a second window. Share only that second window.
• Learners need the People, Processes and Technology and CIA Triad lessons first.
• Leave space on the board for learners' own success criteria for the records application, to compare with the lesson's.
• The lesson takes about 75 minutes. To teach it in two parts, stop after “Accessibility”; the second part opens with the unintended consequences and ends with the MFA decision.
• In presentation mode every step is shown in turns: Next reveals one moment, part or answer at a time, and the instructor view names what is on screen and what comes next.

Steps

1. Introduction Opening

   On screen: the lesson’s title, module and number; Next adds its objectives and key terms, as the lesson page lists them; Next again begins the first step.

   Objectives on screen

   • Judge a security measure by three questions at once: protection, ease of use and whether the work can still be done
   • Show that a restrictive rule can make security worse, by following what people actually do
   • Explain why accessibility means an equally safe route, not a weaker one
   • Recognise a workaround as evidence about a control’s design
   • Choose second sign-in proofs for different people, and say why one answer does not suit everyone

   Purpose: Learners meet a fire door wedged open with a chair and work out, before anything is named, that a measure must also be usable and do its job. The three questions are then named and applied. Every place where intuition misleads opens with a prediction: whether security must make things harder, monthly password changes, a folder staff cannot open, a flood of alerts, and the second sign-in proof for a screen-reader user. The diagram of the restriction with its two routes follows the story it summarises. The habit to build: judge a control by what it makes people actually do, and look for a design that keeps the protection with less difficulty.

2. 1. A door propped open Think 4 min

   Purpose: Find, from a familiar door, that protection alone does not make a measure good.

   Ask

   • The door locks very well. What else would you ask about it?

   Responses to expect

   • “Easy to open”, “wide enough for a wheelchair”, “doesn't jam”. Sort them into ease of use and doing the job, without naming either yet.
   • On screen in turns: the door and the question, its answer, then what happens to security people cannot live with.

   Discussion pause: Collect answers before revealing the explanation.

   In the lesson window

   • Think it through: The door locks very well, yet it ends up protecting nothing. Apart from how well it locks, what else would you ask about a door before calling it a good one?

3. 2. Three questions Explain 6 min

   Purpose: Name the three questions, apply them to a system, and note where the door comparison stops.

   Ask

   • The theatre's booking system cannot print tickets. Which question does it fail?

   Responses to expect

   • Some say usability. Ask whether staff can use it easily, and what it cannot do.
   • On screen in turns: the opening, the three questions one at a time, the table for a computer system with the name SUF, the theatre question and its answer, then where the door comparison stops.

   If the explanation does not land: Use a school gate: does it keep strangers out, can pupils and staff get through quickly, and can deliveries and wheelchairs pass?

   In the lesson window

   • Check your understanding: A theatre’s new booking system keeps out every attacker and is easy to sign in to, but it cannot print the tickets the box office needs. Which of the three does it fail?

4. 3. Thinking beyond a trade-off Predict 5 min

   Purpose: Show that the three do not always conflict, and that the most restrictive option is not automatically the best.

   Ask

   • Must more security always mean harder to use?

   Responses to expect

   • Most say yes. Ask for one change that helps both before revealing the lesson's three.
   • On screen in turns: the question and its answer, when the three pull against each other, three changes that help both, then the question to ask when a control causes problems.

   Misconceptions to challenge

   • A learner may believe: “Security and usability always pull against each other.” Respond: Clear instructions, official routes and safe defaults help both.

   Discussion pause: Ask the class for one change they know that made something both safer and easier.

   In the lesson window

   • Think it through: Must making a system more secure always make it harder to use?

5. 4. A fictional example Experiment 6 min

   Purpose: Have learners define success for a real system under each heading before seeing the lesson's version.

   Ask

   • What would success look like for the records application, under each heading?

   Responses to expect

   • Security answers often stop at “only staff can sign in”. Ask whether every member of staff should see every record.
   • On screen in turns: the school, the heading and the question, its answer, success for each heading one at a time, then why one heading cannot stand in for another.

   Misconceptions to challenge

   • A learner may believe: “If the sign-in page loads, the system works.” Respond: Ask whether the right person can finish the right task safely.

   In the lesson window

   • Think it through: Try it before reading on: for the school’s records application, what would success look like under security, under usability and under functionality?

6. 5. Examine a restrictive password policy Predict 6 min

   Purpose: Follow a restrictive rule to its real effect.

   Ask

   • Monthly password changes: harder or easier to guess?

   Responses to expect

   • Many predict harder. The patterns and notes in steps 2 and 3 usually surprise them.
   • On screen in turns: the rule, the prediction and its answer, the worked example up to how people cope, the judged result, a better design, then what the example does not show.

   Misconceptions to challenge

   • A learner may believe: “More friction means more security.” Respond: Judge the result, not the intention: the rule made passwords easier to guess.

   If the explanation does not land: Ask learners how they themselves would cope with a new password every month.

   In the lesson window

   • Think it through: Predict: once everyone must change their password every 30 days, will the school’s passwords become harder or easier to guess?

7. 6. Accessibility Predict 7 min

   Purpose: Establish that accessibility means an equally safe route, and that the whole journey, including recovery, must work.

   Ask

   • Someone cannot use the only approved way in. What should happen?

   Responses to expect

   • A colleague's account, or an exemption, may come up. Ask what each does to the protection and to the records.
   • On screen in turns: the question and its answer, what accessible means, the fingerprint reader, then the design checklist.

   Misconceptions to challenge

   • A learner may believe: “Accessibility means lowering security.” Respond: It means an approved route that works for each authorised person and meets the same requirement.

   If the explanation does not land: Plan the bad day for the fingerprint reader: what happens when someone’s finger is cut and bandaged?

   In the lesson window

   • Think it through: A fully authorised member of staff cannot use the only approved way of signing in. What should happen?

8. 7. Unintended consequences of poorly designed controls Predict 11 min

   Purpose: Predict how a control that blocks legitimate work creates new exposure, and how too many alerts hide the important one.

   Ask

   • The assistants cannot open the folder and do not know how to ask. What happens next?
   • What happens to the three important alerts after a fortnight?
   • And the fix?

   Responses to expect

   • Most predict workarounds; press for the fix, which is an authorised route rather than reopening the folder.
   • “Turn them off” is a common fix. Return to the warning nobody read.
   • Diagram: let the class describe the authorised route before it appears. The point is that the fix is a route, not removing the restriction.
   • The check question on the alerts now comes before the explanation of the fix, so the class reasons it out first.
   • On screen in turns: the folder restriction and its question, the answer, what happened within a week, the diagram with only the route that has no way to ask, then the authorised route, the fix in words, the alerts scenario and its question, the answer, the check question on fixing the alerts and its answer, then why more alerts did not help.

   In the lesson window

   • Think it through: The teaching assistants still need the list to set up exam rooms, but cannot open the folder and do not know how to ask. What do you expect to happen?
   • Think it through: Predict: what happens to those three important alerts after a fortnight?
   • Check your understanding: What is the best fix for the 400 alerts a day?

9. 8. Worked decision: introducing MFA Explain 8 min

   Purpose: Set out the three methods and three people, and predict a method for one of them before the table.

   Ask

   • Which method would you give Mr Clarke?

   Responses to expect

   • The authenticator app is a common first choice; the 30-second code is the problem.
   • On screen in turns: what MFA is, the three methods, the three members of staff, the question about Mr Clarke and its answer, then the comparison table.

   Misconceptions to challenge

   • A learner may believe: “All MFA is equally strong.” Respond: The three resist different attacks; only the key refuses a fake website.

   Discussion pause: Let the class choose a method for each member of staff before the table appears.

   In the lesson window

   • Think it through: Before you read the table: which of the three methods would you give Mr Clarke, who uses a screen reader?

10. 9. Follow the decision through Explain 9 min

    Purpose: Walk through the decision: standard method, equally safe alternative, strongest method for the riskiest account, a recovery route and an owner.

    Ask

    • What is most likely to tempt someone into sharing an account?
    • Why is the security key not a weaker exception?

    Responses to expect

    • Lost or forgotten devices.
    • It is the strongest of the three, so the alternative raises protection.
    • On screen in turns: the bad-day question and its answer, the decision’s first two steps, then steps three to five, then six and seven, the result, what changes if one fact changes, the optional note on passwordless sign-in, then what a workaround tells you.

    In the lesson window

    • Think it through: Suppose the new sign-in is working well. What single event is most likely to tempt someone into sharing an account?

11. 10. Apply it in a new situation Apply 4 min

    Purpose: Set up independent application, ideally on a later day.

    Ask

    • Who will try these now, and who later in the week?

    Responses to expect

    • The council question checks an equally safe alternative; the ward question checks a workaround read as evidence about design.
    • On screen in turns: the council question and its answer, then the hospital question and its answer.

    In the lesson window

    • Apply it: To keep out automated attacks, a council’s website makes every visitor solve a picture puzzle that a screen reader cannot describe. Blind residents now cannot pay their council tax online. What is the best response?
    • Apply it: A hospital ward makes nurses sign in again every two minutes on shared computers. Nurses now leave one colleague signed in all shift, and everyone works under that one sign-in. What does this show?

12. 11. Check your understanding Check 4 min

    Purpose: Check the lesson against the approved revision-bank questions.

    Ask

    • Answer individually, then compare before revealing.

    Responses to expect

    • The accessible MFA question links back to the worked decision.
    • On screen in turns: each revision question and its answer, then where to practise. The questions are interactive: learners choose and check before the explanation opens.

13. 12. Key takeaway Consolidate 5 min

    Purpose: Summarise the four questions to ask about any control, the five points, the key terms and the misunderstandings.

    Ask

    • Without looking: what four questions would you ask about a new control?

    Responses to expect

    • Does it address the risk, can people use it, does the work still happen, who owns it.
    • On screen in turns: the four questions, how the three can reinforce each other, the summary, the key terms, then the common misunderstandings.

14. Lesson recap Closing

    On screen: the lesson’s objectives again; Next adds the closing question, which asks the class to explain each one in their own words without looking back. It says nothing about what anyone has learnt: use the answers to decide what to revisit.

    Points to listen for

    • Protection, ease of use and getting the work done: all three, at once.
    • Inconvenience is not evidence of protection.
    • Good design often improves all three together.
    • An accessible route is an equally safe one.
    • A workaround tells you something about the design.

Consolidation

• Protection, ease of use and getting the work done: all three, at once.
• Inconvenience is not evidence of protection.
• Good design often improves all three together.
• An accessible route is an equally safe one.
• A workaround tells you something about the design.