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UK AISI Safety Cases

This page is an explanatory crosswalk between Structural Assurability and safety-case work published by the UK AI Security Institute.

It does not claim that AISI adopts Structural Assurability.

Safety-Case Structure

AISI safety-case work uses structured, evidence-based arguments to support safety claims.

Its published cyber inability template uses a Claims-Arguments-Evidence structure and connects:

  • top-level claims
  • subclaims
  • risk models
  • proxy tasks
  • evaluation settings
  • evaluation results

Structural Assurability addresses a complementary question:

Does the evaluated system and its evidence environment make the evidence required by such an argument obtainable under the evaluator's actual conditions?

Structural Crosswalk

The relationship can be represented as:

safety claim
     ↓
subclaims and required distinctions
     ↓
evaluation design
     ↓
required evidence
     ↓
structural obtainability of that evidence
     ↓
evaluation results
     ↓
safety-case argument

Structural Assurability concerns the structural obtainability and capability portion of this sequence.

It does not establish the safety claim.

Independent Evidence

The formal theory distinguishes structural properties such as:

  • observability
  • traceability
  • reconstructability
  • independence
  • integrity
  • evidence coverage

These properties can matter differently depending on the safety claim.

For example, detailed internal traces and independently generated external evidence may enable different assurance-relevant capabilities.

Neither is automatically superior for every claim.

Structural Assurability Source of Truth

SE/StructuralAssurability/Layer30_Core/Capability.lean
SE/StructuralAssurability/Layer30_Core/Assurability.lean
SE/StructuralAssurability/Layer40_Order/Incomparability.lean
SE/StructuralAssurability/Layer50_Properties/Independence.lean
SE/StructuralAssurability/Layer50_Properties/Integrity.lean
SE/StructuralAssurability/Layer50_Properties/EvidenceCoverage.lean
SE/StructuralAssurability/Layer90_Examples/Case3_Incomparability.lean

External Source of Truth

Relevant AISI sources include:

  • Safety case template for frontier AI: A cyber inability argument
  • AISI Safety Cases research collection

AISI publications remain authoritative for AISI safety-case methods.