Security vs Usability
Varying control by the value of the action rather than uniformly.
4 to work through
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intermediate
A B2B SaaS with 900 tenants makes SAML single sign-on mandatory for every enterprise-plan tenant after a security review, and local passwords are deleted. Six weeks later an identity provider outage locks about 40 tenants out for three hours and support has no way to help. What did the mandate buy, what did it pay, and what should have existed first?
2 min answer -
intermediate
A security control is being circumvented by most of the team. What do you conclude and what do you do?
2 min answer -
advanced
A consumer finance product must balance fraud controls against onboarding friction. How should that trade-off be made rather than argued?
2 min answer -
advanced
A security control materially reduces risk and adds friction to a developer workflow used thousands of times a day. How should the trade-off be made?
2 min answer
3 terms in this topic
False-Decline Cost
The value lost to legitimate customers rejected or deterred by a control - invisible in fraud metrics, frequently larger than the losses prevented, a…
conceptFriction Budget
The limited amount of security friction users will absorb before they work around it, making usability a security property rather than its opponent.
conceptSecurity versus Usability
Controls that impose too much friction get circumvented — so the usable control is frequently the more secure one.
Neighbouring topics
Architecture Decision-Making
General material on making and recording architectural decisions.
Architecture Decision Records
One decision, its context, alternatives and consequences, kept immutable.
Reversibility
One-way and two-way doors, and buying optionality deliberately.
Build vs Buy
Differentiation, five-year TCO, and the exit cost of each option.
Monolith vs Microservices
A team-topology decision far more often than a technology one.
SQL vs NoSQL
Decided by access patterns and query flexibility, not by data volume.
Sync vs Async
Whether the caller's outcome depends on the callee's response.
Strong vs Eventual Consistency
A per-operation decision, resolved by what a stale read would cost.
Managed vs Self-Managed
Trading control and unit cost against operational attention.
Serverless vs Containers
Spiky and event-driven versus sustained throughput.
Single vs Multi-Region
Driven by RTO, RPO and residency rather than by ambition.
Centralised vs Distributed
Shared platform leverage against team autonomy.
Performance vs Cost
Buying latency, and knowing what the last millisecond is worth.
Reliability vs Complexity
Mechanisms that add availability and add failure modes.
Delivery vs Maintainability
Fast in the cheap places, careful in the expensive ones.
Deciding Under Uncertainty
Bounding the downside and buying information cheaply.
Trade-off Analysis Methods
ATAM, scenarios, and naming the points where qualities conflict.
Technology Selection
Evaluating options against drivers rather than against enthusiasm.
Decision Practice
Thresholds, review, supersession and keeping the log alive.