Trust Boundaries

A trust boundary identifies where data, responsibility or authority moves between components or actors with different trust assumptions.

Example

AI Application
     │
     │ unverified output
     ▼
┌─────────────────────────────┐
│       TRUST BOUNDARY        │
└─────────────────────────────┘
     │
     ▼
Evidence Capture
     │
     ▼
Integrity Protection
     │
     ▼
Independent Verification

Questions at every boundary

Developers should ask:

What enters the boundary?
Who controls it?
Which fields are trusted?
Which fields are verified?
What evidence is preserved?
What happens when validation fails?

Boundary types

Typical DigiEmu workflows may include boundaries between:

application and verification layer
model and tool execution
source repository and build
local system and transported evidence
evidence producer and reviewer
signer and verifier

Explicit assumptions

A boundary should document assumptions rather than hide them.

Example:

Trusted:
- published verification schema
- verification implementation
- selected cryptographic primitive

Not automatically trusted:
- application UI
- external claims
- mutable local files
- network transport

Principle

Trust should be declared. Integrity should be verified.

Next

Continue with Evidence Protection →.