Authentication proves identity, authorization limits actions, TLS protects data in transit, and disaster recovery restores service and data after a severe failure. These controls cover different risks and must be tested together.
Authentication proves identity, authorization limits actions, TLS protects data in transit, and disaster recovery restores service and data after a severe failure. These controls cover different risks and must be tested together.
| Question | Practical answer |
|---|---|
| When is it useful? | In a small real-world scenario, draw the parts involved, follow one request or decision from start to finish, and mark the evidence produced at each step. |
| What should you do? | Draw a login-to-backup flow for a notes app; define two roles, confirm HTTPS, take a backup, delete test data, and restore it. |
| How do you know it worked? | The result can be repeated from your notes, and each important claim is supported by an output, measurement, query result, or reviewable artifact. |
| Common failure | A common mistake is choosing a tool or pattern before stating the problem, constraints, and success measure. |
flowchart LR
A[Question] --> B[Authentication, authorization, TLS, and di]
B --> C[Small example]
C --> D[Evidence]
The important idea is not to stop at a definition: connect the concept to a small example and observable evidence.
In a small real-world scenario, draw the parts involved, follow one request or decision from start to finish, and mark the evidence produced at each step.
Before acting, write the success signal. Change one condition at a time, observe the result, and record assumptions. For Authentication, authorization, TLS, and disaster recovery, this separates what you know from what you are merely guessing.
Goal: Draw a login-to-backup flow for a notes app; define two roles, confirm HTTPS, take a backup, delete test data, and restore it.
Expected result: The result can be repeated from your notes, and each important claim is supported by an output, measurement, query result, or reviewable artifact.
A common mistake is choosing a tool or pattern before stating the problem, constraints, and success measure.
When the result differs from your prediction, do not change many things at once. Check inputs, versions, environment, permissions, and logs, then repeat from the smallest example.
Use the linked resource or repository at the end of the page when you need a full implementation. Check current versions before applying commands to a real project.
Learn system design as a sequence of decisions, using a small learning platform as the running example.
Functional requirements describe behavior users need; non-functional requirements define qualities and constraints such as latency, accessibility, security, capacity, and recovery.
High-level design explains system boundaries, data flow, dependencies, and major tradeoffs; low-level design specifies components, interfaces, data models, algorithms, and failure handling.