computer science

Trusted path

Trusted path is a computer science 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 Trusted path rather than just read about it. In short: A trusted path or trusted channel is a mechanism that provides confidence that the user is communicating with what the user intended to communicate with, ensuring that attackers can't intercept or modify whatever information is being communicated. The term was initially introduced by Orange Book.

Key takeaways

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

Reference excerpt

A trusted path or trusted channel is a mechanism that provides confidence that the user is communicating with what the user intended to communicate with, ensuring that attackers can't intercept or modify whatever information is being communicated. The term was initially introduced by Orange Book. As its security architecture concept, it can be implemented with any technical safeguards suitable for particular environment and risk profile.

Examples

Electronic signature In Common Criteria and European Union electronic signature standards trusted path and trusted channel describe techniques that prevent interception or tampering with sensitive data as it passes through various system components:

trusted path — protects data from the user and a security component (e.g. PIN sent to a smart card to unblock it for digital signature), trusted channel — protects data between security component and other information resources (e.g. data read from a file and sent to the smart card for signature).

User login One of popular techniques for password stealing in Microsoft Windows was login spoofing, which was based on programs that simulated operating system's login prompt. When users try to log in, the fake login program can then capture user passwords for later use. As a safeguard Windows NT introduced Ctrl-Alt-Del sequence as secure attention key to escape any third party programs and invoke system login prompt. A similar problem arises in case of websites requiring authentication, where the user is expected to enter their credentials without actually knowing if the website is not spoofed. HTTPS mitigates this attack by first authenticating the server to the user (using trust anchor and certification path validation algorithm), and only then displaying the login form.

References

Worked examples

Example 1 — a first encounter with Trusted path

Start with the simplest possible case. Write down what Trusted path claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, 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 Trusted path 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 Trusted path 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 Trusted path

In research: Trusted path appears in computer science 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 Trusted path 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: Trusted path is common in secondary-school and first-year university syllabi. It links to neighbouring topics Computer network security, so understanding it makes those chapters shorter.
In everyday life: Look for Trusted path 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 Trusted path in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Trusted path 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 Trusted path out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Trusted path in simple terms?

Why does Trusted path matter?

Because it connects several computer science 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 Trusted path?

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 Trusted path.