SPRG Logs

A requirement is (1) a condition or capability a user needs to solve a problem, (2) a condition or capability a system must possess to satisfy a contract or standard, or (3) a documented representation of (1) or (2). The three-part definition is deliberately layered, because the...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

You can choose the instrument (natural language → structured models → interaction models → formal model), the structure, the precision, and the depth (deepness) of the representation. * Four dials you set independently; turning any of them up costs more effort, so each is scaled...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

The later you find it, the more it costs — from x1 in requirements to a mean of about x250 once the system is in operations, which is why rework and bug-fixing can swallow up to half a project's effort. * The multipliers on a log scale: the range per phase, with the mean joining...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

A functional requirement says what the system does — a result or behaviour a function must provide; a quality requirement says how well it does it (performance, availability, security…) and is defined as everything not covered by the functional ones. This is the most fundamental...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

Not "zero vulnerabilities" but "no well-known vulnerabilities in the code" — reached by knowing the common vulnerability types, avoiding the well-known mistakes, and reusing proven countermeasures and patterns instead of inventing your own. Perfect security is not an achievable g...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

Software Assurance is the level of confidence that software is free of vulnerabilities and behaves as intended — its two pillars are Trustworthiness and Predictable Execution. * The two pillars as independent axes — three of the four quadrants are assurance failures. * Software...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

Elicit the stakeholders' requirements, document them suitably, validate and verify them, and manage them — and you do all four across the entire life cycle of the system, not just once at the start. * Management is drawn as the band around the other three, not as a fourth step i...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

Business analysis identifies business needs and determines solutions to business problems — the solution may not be software at all; requirements engineering is the narrower process of formulating, documenting and maintaining a system's software requirements. * Requirements engi...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

The system boundary draws the line between the system and its environment; the context boundary draws a second, outer line between the environment that matters and the environment you can ignore. * The system boundary separates the system from its environment; the context bounda...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026

The goal is to know the relevant requirements, reach a consensus among stakeholders about them, document them to standards, and manage them systematically — all to minimise the risk of delivering a system that does not meet the stakeholders' real needs. Requirements engineering i...

Quiz: SPRG / Security Requirements Fundamentals | updated: Aug 27, 2026