Chapter 1 · Computer Networks

1.16Usability and Security Tradeoffs

Why making a system safer can make it harder to use, and why good systems balance both.

Written and checked by Muhammad Raheel(opens in a new tab)

Full Stack Developer · AI Engineer · Reviewed 21 Oct 2026 · 2 min read

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Every system has two goals that pull in opposite directions. People want it to be easy to use. They also want it to be safe. This last topic of Chapter 1 explains why you often cannot have the most of both at once. A "tradeoff" means you gain one thing by giving up a little of another.

Usability

A usable system is simple and clear. You can learn it quickly, and you can finish tasks without confusion. Good usability saves time and effort, and it makes users happier with the system. The book calls this user satisfaction.

Security

Security stops people who have no permission from getting in. It protects against viruses and hackers, and it keeps information private and safe. Strong security reduces risks and damage. The book says every system needs basic security.

Tradeoffs Between Usability and Security

Here is the problem. The book gives three ways in which more security makes a system harder to use:

Increasing security can make systems harder to use.
Strong passwords are difficult to remember.
Extra login steps slow down users.

It also shows the other side:

Simple systems are easier but less secure.
Removing security increases risk.

So neither extreme works. A system with no security is easy, but anyone can break in. A system with too much security is safe, but people struggle to use it. The book's conclusion is short:

A balance with usability on the left and security on the right; more security makes the system harder to use, a simpler system is less secure

Practice this topic

All MCQs of this chapter with answers

Short questions

1.What is usability?2 marks
Answer
From the book: "Usability means how easy a system is to use. A usable system is simple and clear. Users can learn it quickly."
2.What is security?2 marks
Answer
From the book: "Security means protecting systems and data. It prevents unauthorized access. Security protects against viruses and hackers. It keeps information private and safe."
3.Write any two benefits of good usability.2 marks
Answer
From the book: "Tasks can be done without confusion. Good usability saves time and effort. It improves user satisfaction." Any two of these.
4.How can increasing security make a system harder to use?3 marks
Answer
From the book: "Increasing security can make systems harder to use. Strong passwords are difficult to remember. Extra login steps slow down users."
5.Why is a balance required between usability and security?3 marks
Answer
From the book: "Simple systems are easier but less secure. Removing security increases risk." But "Increasing security can make systems harder to use." So "A balance is required for safe and easy use."

Long questions

1.Define usability and security. Explain the tradeoffs between usability and security.6 marks
Answer
1.16 is one short page (two paragraphs and one sub-heading), so one long question covers it. Use the book's text:
1. Usability (verbatim): "Usability means how easy a system is to use. A usable system is simple and clear. Users can learn it quickly. Tasks can be done without confusion. Good usability saves time and effort. It improves user satisfaction."
2. Security (verbatim): "Security means protecting systems and data. It prevents unauthorized access. Security protects against viruses and hackers. It keeps information private and safe. Strong security reduces risks and damage. Every system needs basic security."
3. Tradeoffs Between Usability and Security (verbatim):
  
  "Increasing security can make systems harder to use."
  
  "Strong passwords are difficult to remember."
  
  "Extra login steps slow down users."
  
  "Simple systems are easier but less secure."
  
  "Removing security increases risk."
4. Conclusion: "A balance is required for safe and easy use."
Aim for 150-250 words.

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