engineering

Intrusion tolerance

Intrusion tolerance is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Intrusion tolerance rather than just read about it. In short: Intrusion tolerance is a fault-tolerant design approach to defending information systems against malicious attacks. In that sense, it is also a computer security approach.

Key takeaways

Intrusion tolerance belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Intrusion tolerance to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Intrusion tolerance from memory before moving on to harder problems.

Reference excerpt

Intrusion tolerance is a fault-tolerant design approach to defending information systems against malicious attacks. In that sense, it is also a computer security approach. Abandoning the conventional aim of preventing all intrusions, intrusion tolerance instead calls for triggering mechanisms that prevent intrusions from leading to a system security failure.

Distributed computing In distributed computing there are two major variants of intrusion tolerance mechanisms: mechanisms based on redundancy, such as the Byzantine fault tolerance, as well as mechanisms based on intrusion detection as implemented in intrusion detection system) and intrusion reaction.

Intrusion-tolerant server architectures Intrusion-tolerance has started to influence the design of server architectures in academic institutions, and industry. Examples of such server architectures include KARMA, Splunk IT Service Intelligence (ITSI), project ITUA, and the practical Byzantine Fault Tolerance (pBFT) model.

See also Intrusion detection system evasion techniques

References

Worked examples

Example 1 — a first encounter with Intrusion tolerance

Start with the simplest possible case. Write down what Intrusion tolerance claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Intrusion tolerance before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Intrusion tolerance ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Intrusion tolerance

In research: Intrusion tolerance appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Intrusion tolerance in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Intrusion tolerance is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cybersecurity engineering, Fault tolerance, so understanding it makes those chapters shorter.
In everyday life: Look for Intrusion tolerance outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Intrusion tolerance in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Intrusion tolerance means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Intrusion tolerance out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Intrusion tolerance in simple terms?

Intrusion tolerance is a fault-tolerant design approach to defending information systems against malicious attacks. In that sense, it is also a computer security approach.

Why does Intrusion tolerance matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Intrusion tolerance?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Intrusion tolerance.