SFS C: Interfacing Protocols and APIs
Assess the trust boundaries and behavior of interfaces used to exchange data or commands between services, devices, and external systems.
Scope and boundaries
This set covers API contracts, message protocols such as MQTT, interface authentication and authorization, input validation, error handling, and control of exchanged data. It includes integration tests and mock interfaces where they support verification. Questions should identify the communicating parties, allowed operations, and evidence that the interface enforces its stated conditions. Network transport restrictions belong to SFS 5, identity management to SFS 3, and data lifecycle rules to SFS 4.
The sixteen questions
Each SF position is one question. Both positions run from 0 to F.
| SF | Question page | Authoring record |
|---|---|---|
| 0 | SF 0 | 00C0 |
| 1 | SF 1 | 00C1 |
| 2 | SF 2 | 00C2 |
| 3 | SF 3 | 00C3 |
| 4 | SF 4 | 00C4 |
| 5 | SF 5 | 00C5 |
| 6 | SF 6 | 00C6 |
| 7 | SF 7 | 00C7 |
| 8 | SF 8 | 00C8 |
| 9 | SF 9 | 00C9 |
| A | SF A | 00CA |
| B | SF B | 00CB |
| C | SF C | 00CC |
| D | SF D | 00CD |
| E | SF E | 00CE |
| F | SF F | 00CF |
From questions to a profile
Only reviewed, accepted 0/1 assessments can populate the sixteen-bit set profile. SF 0 is the most significant bit and SF F the least significant bit. The completed result uses four hexadecimal digits, including leading zeros. A catalog definition does not establish a completed assessment profile.
Read assessment and validation, then encoding. A set profile preserves individual answers; it is not a summed security score.