Model Supply Chain Security

End-to-end model supply chain with checkpoint gates, attack vectors, and mitigations for tampered weights, poisoned models, and malicious tokenizers.

EMEP treats every model as a software artifact with a verifiable provenance chain. This page defines the full supply chain from source discovery through deployment, with checkpoint gates that enforce integrity at each transition.

Supply Chain Flow

Each gate is a hard stop. A failure at any gate triggers quarantine and incident logging.

Checkpoint Gates

Gate	Check	Component	Failure Action
Gate 1	SHA-256 hash matches published value	ModelLoader	Quarantine; alert ops
Gate 2	Signature verifies against known key	ArtifactStore	Quarantine; flag key rotation
Gate 3	Tensor shape match; no NaN/Inf spikes	MergeEngine	Quarantine; abort merge
Gate 4	Safety eval PASS; no regression on Validation Set	EvaluationEngine	Quarantine; candidate FAIL

Attack Vectors

Vector	Description	Mitigation
Model poisoning	Weights manipulated to inject backdoor behavior	Hash verification + signature check at Gate 1 and 2
Dependency confusion	Malicious package with same name as internal dependency	Exact pinning + SBOM + offline mirror
Tampered weights	Weights replaced after download	Hash check at every load; signed artifacts
Malicious tokenizer	Tokenizer vocab or rules altered to leak data or bias output	Tokenizer hash pinned in registry; compatibility check
Backdoor triggers	Hidden triggers activate harmful outputs	Safety evaluation at Gate 4; red-teaming
License laundering	Model released under incompatible license after merge	License compliance matrix enforced before merge

Provenance Chain

Every model in the registry carries a provenance record:

• Source URL and commit hash
• Download timestamp and verifier identity
• Hash algorithm and value
• Signature and key identifier
• Merge parents and strategy
• Evaluation results and benchmark version

The provenance chain is immutable after release. Corrections create a new release with a superseded-by link.

Incident Response

A quarantined model is moved to an isolated storage prefix with no read access from MergeEngine, EvaluationEngine, or DeploymentManager. An alert fires with severity P2. The incident record includes the gate, the check that failed, the artifact ID, and the timestamp. Recovery requires manual review and explicit unquarantine by an operator with security role.

Cross-Links

• Artifact Signing
• License Compliance
• Security Requirements
• Model Provenance