Begin with simple categories for a user authentication project and refine them as you learn

Outline

• Hook: A quick reality check for anyone wrestling with requirements in a user authentication project.

• Core message: The statement “Good start but groupings can be refined later” is the most true—requirements categorization is iterative, not a one-and-done task.

• Sections preview:

• Why categorization matters in the real world

• How to start grouping, without getting stuck

• A concrete example: user authentication requirements

• How refinement happens over time (stakeholders, market shifts, risk)

• The balance between alignment to specifications and flexible thinking

• Practical, actionable tips you can apply next

• Gentle wrap-up and takeaways

What’s this really all about?

Let me ask you a question: when you’re building a user authentication system, what’s the first thing you should do with the requirements? If you said, “I’ll just write everything down and call it a day,” you’re not alone. Yet that approach rarely sticks. Requirements are living things. They grow, shift, and sometimes even move from one category to another as you learn more, gather feedback, or see a real user pattern emerge.

The most true statement, in the context of categorizing requirements for a user authentication application, is C: Good start but groupings can be refined later. It’s a recognition that we begin with a practical structure to gain clarity, and then we sharpen that structure as the project unfolds. It’s not about chaos or indecision; it’s about embracing an iterative mindset—one that matches how software projects actually behave in the wild.

Why categorization matters (even if it’s not perfect on day one)

In requirements engineering, categorization isn’t about boxing things in permanently. It’s about creating a map that helps teams see where to focus, how different pieces relate, and what to negotiate first. For an authentication app, you’re juggling security, usability, performance, legality, and maintainability. Put differently: you need a way to see which requirements touch security, which touch user experience, and which are about compliance or data privacy.

If you skip categorization, several things can go off the rails:

• You miss cross-cutting concerns. A password policy affects security and usability at the same time.

• Priorities blur. Is a faster login more important than a stronger MFA? Without groups, it’s easy to flip-flop between priorities.

• Traceability gets messy. If you can’t trace a requirement to a category, you’ll struggle to show stakeholders how decisions align with goals.

But the flip side is equally true: rigid, over-structured taxonomies can trap you. If you try to lock everything into a single framework too early, you’ll miss emerging needs and the natural evolution of the project. That’s why the pragmatic answer is to start with a sensible grouping and refine later.

A practical starter approach for an authentication system

Here’s a straightforward way to begin, without getting bogged down in jargon:

• Functional groupings: What the system must do

• Core login/logout flows

• Password management (reset, change, strength checks)

• Multi-factor authentication (MFA) options

• Session lifecycle (timeout, renewal, revocation)

• Account recovery and lockout behavior

• Non-functional groupings: How it must perform

• Security attributes (confidentiality, integrity, authentication strength)

• Usability attributes (learnability, error messages, help paths)

• Performance and reliability (latency targets, availability, failover)

• Privacy and data handling (audit trails, data minimization)

• Compliance considerations (log retention, access controls)

• Quality attributes as cross-cutting themes

• Auditing and traceability

• Resilience to abuse (brute force protection, bot management)

• Accessibility (keyboard navigation, screen reader support)

This is intentionally broad, so you can place individual requirements under a few overarching headings. The goal isn’t to capture every single line item in one table, but to create a working scaffold that helps the team reason about what matters most in the moment.

A concrete example: mapping requirements for a login feature

Let’s walk through a mini-example to illustrate how this works in practice.

• Functional: User can log in with username and password.

• Category: Functional

• Related concerns: security, usability

• Functional: System supports MFA (e.g., authenticator app, SMS codes).

• Category: Functional

• Related concerns: security, usability, risk

• Non-functional: Login response time under 200 milliseconds under normal load.

• Category: Performance

• Non-functional: Passwords stored with salted hashing; password policy enforces length and complexity.

• Category: Security

• Functional: User can reset password via email link.

• Category: Functional

• Non-functional: Audit log of login attempts (successful and failed) retained for 12 months.

• Category: Compliance/Audit

• Cross-cutting: Account lockout after 5 failed attempts within 15 minutes.

• Category: Security + Usability tension (balance)

• Regulatory: Data retention policies for authentication events comply with GDPR/region-specific rules.

• Category: Privacy/Compliance

Notice how the grouping isn’t just about list-making. It helps you see where the biggest risks live, where you need to invest time, and how changes in one area might ripple into another. It also makes it easier to explain decisions to stakeholders who care about different angles—security folks might focus on the security and audit aspects, while product folks zero in on usability and performance.

Refinement as the project learns (the iterative spirit)

Here’s the heart of the matter: you don’t get one perfect categorization and call it a day. You refine as you go. Why would you do that? Because real projects start with imperfect knowledge, and that’s perfectly normal.

• Stakeholder feedback: A security officer might push to elevate certain requirements into a stricter security category. A product manager might push to re-balance usability vs. security after user testing.

• Market and risk shifts: If a new threat emerges or a vendor starts offering a different MFA option, you might regroup certain requirements under different headings to reflect new priorities.

• Technical discovery: Early assumptions about latency or data flows may change once you run practical experiments or proofs of concept.

This is not a failure of planning; it’s the practical outcome of learning. In IREB terms, it aligns with the idea that requirements engineering is an ongoing, iterative discipline—stakeholders, risk, and technology inform each other in cycles.

Why alignment to specification matters, but isn’t the whole story

Setting things up to align with a specification or standard is valuable. It helps ensure coverage, consistency, and a shared understanding across teams. But the real advantage comes from allowing that alignment to be a living guideline rather than a fixed rule. In authentication, standards may point you toward categories like security and privacy, but how you group and re-group practical requirements often depends on project realities, user needs, and risk appetite.

In other words: specify, but stay flexible. The best teams treat categorization as a scaffolding that evolves with the project. And that’s precisely what the “good start, refined later” mindset is all about.

Tips to keep your categorization healthy and productive

• Start simple, with just a few broad buckets (Functional, Security, Usability, Privacy, Performance, Compliance).

• Keep traceability alive. Every requirement should link to a goal and to one or more categories.

• Revisit groups at milestones or after significant feedback. Don’t wait for the end of the project to adjust.

• Don’t chase the perfect taxonomy on day one. Favor clarity and usefulness over completeness.

• Use real-world scenarios to test your categories. If a scenario straddles two buckets, note the cross-cutting implications and how you’ll handle them.

• Document the rationale for moving a requirement from one category to another. It helps future teams understand why things changed.

A few rhetorical nudges to keep the flow human (without losing rigor)

• Ever notice how a single login rule touches security, usability, and compliance all at once? That’s exactly why grouping is both an art and a science.

• Think of your categories as lanes on a highway. They guide traffic; they don’t lock you into a forever lane.

• When in doubt, ask: does this grouping help the team decide what to do next, and why it matters to users?

Balancing tone for different readers

For a general audience, a touch more storytelling helps. A relatable analogy—like organizing a closet by function (work clothes vs. casual wear) but planning to re-sort as your style changes—can make the point stick. For a professional audience, keep the explanations concise, with clear implications for risk, schedule, and scope, while still letting a few vivid examples land.

Putting it all together: the practical takeaway

If you’re evaluating a statement about categorizing requirements for a user authentication app, option C is the most accurate. Start with a sensible grouping to bring order to chaos, then refine as you learn. It keeps teams aligned, helps stakeholders see where decisions matter, and provides a flexible path through the inevitable changes a project will face.

To wrap up, think of categorization as a living blueprint. It helps you communicate, prioritize, and adapt without losing sight of security, usability, and user trust. And isn’t that what a robust authentication system is really about? Clear categories, thoughtful refinement, and a steady eye on the goals that matter to real users.

If you want a quick scaffold for your next requirements session, you can try this: begin with Functional and Security as the core pillars, add Usability and Privacy as essential cross-cutting lenses, then layer in Compliance and Performance as needed by the project stage. Revisit every major decision every few weeks, invite stakeholder feedback, and document the why behind any changes. You’ll be surprised how much smoother the conversation becomes when everyone’s looking at the same map—and the map keeps changing as the landscape does.

In short: you don’t have to have all the answers right away. You just need a thoughtful starting point, and a willingness to refine as you go. That’s how good requirements work in the real world—and that, right there, is precisely what makes option C the most true answer.