Computing systems, networks and requirements
Đã giới thiệu| English | Ý nghĩa |
|---|---|
| authentication/ɔːˌθentɪˈkeɪʃn/ | xác thực |
| authorization/ˌɔːθəraɪˈzeɪʃn/ | phân quyền |
What would explain this observation?
- A school booking system can calculate correctly and still fail if users lose access or records are disclosed. Success includes the system context.
Build the model
- A computer system combines hardware, software, data and people.
- A network enables communication using protocols.
- Requirements should distinguish function from constraints such as availability, security and accessibility.
- authentication 身份验证: Checking an asserted identity.
- authorization 授权: Determining permitted actions.
Which question concerns authorization?
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Authorization asks what an identified user may do - "may this user edit this record?" "Who are you?" is authentication, and screen colour is neither.
Match each technical term to its precise meaning.
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Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Separate authentication from authorization.
- Authentication checks identity; authorization determines permitted actions.
- A threat model connects a valuable asset, a possible attack and an appropriate control.
In the lab: Use a fictitious school dataset to define users and permissions. Draw data flows, compare validation and verification, and specify tests for normal, boundary and invalid input. Do not use real credentials or student records in exercises.
Which two habits make the investigation or model in this case more defensible?
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Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: a file contains 12 megabytes, where this example defines one megabyte as one million bytes.
- Bits = bytes×8 = 12×1,000,000×8 = 96,000,000 bits.
- At 8,000,000 bits per second, ideal time = size/rate = 12 s, excluding overhead.
Your turn: A 40 million bit file transfers at 5 million bits per second. Find ideal time.
A 40 million bit file transfers at 5 million bits per second. Find ideal time.
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The result is 8 s. Known: 40 million bits at 5 million bits per second. Use ideal time = size / rate. Time = 40,000,000 / 5,000,000 = 8 s. Real transfers are slower once overhead and sharing are included.
Check the conclusion and its limits
- Bandwidth is not actual end-to-end throughput.
- Encryption does not by itself ensure correct authorization or remove every security risk.
Not true: Encryption guarantees that every user has appropriate access permissions. Encryption protects content from being read by others; it does not decide who is allowed to do what. Authorization is a separate check of permissions, and encryption alone leaves it untouched.
- A computer system combines hardware, software, data and people.
- Separate authentication from authorization.
- Watch for: bandwidth is not actual end-to-end throughput.
Encryption protects content from being read by others; it does not decide who is allowed to do what.
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True. Encryption protects content from being read by others; it does not decide who is allowed to do what. Authorization is a separate check of permissions, and encryption alone leaves it untouched.
Checking an asserted identity: write the technical term.
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authentication means Checking an asserted identity.