領収書と検証

TL;DR: Every HELM decision produces a cryptographic receipt. Receipts form a hash-linked chain you can verify offline with helm verify --bundle evidence.tar.

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Receipt structure

Each receipt contains everything needed to independently verify a decision:

Field	Value
receipt_hash	SHA-256 of the canonical receipt
prev_hash	Hash chain link to previous receipt
lamport_clock	Causal ordering (monotonic)
principal	Who initiated the tool call
tool_name	What was invoked
args_hash	SHA-256 of JCS-canonicalized input
output_hash	SHA-256 of tool output
reason_code	Why: ALLOW or DENY
timestamp	ISO 8601
signature	Ed25519

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Verification checks

The verifier performs three checks on the receipt chain:

Check	Rule	Catches
Hash integrity	receipt_hash == SHA-256(receipt)	Modified receipts
PrevHash chaining	prev_hash == previous.receipt_hash	Deleted receipts
Clock monotonicity	lamport_clock > previous.lamport_clock	Reordered receipts

JCS canonicalization (RFC 8785) ensures deterministic serialization for consistent hashes.

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Verify an EvidencePack

helm export --evidence ./data/evidence --out evidence.tar
helm verify --bundle evidence.tar

Expected: verification: PASS

The EvidencePack is a deterministic tar archive — sorted file paths, epoch mtime, root uid/gid. Same content always produces the same SHA-256.

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Fetch receipts from the standalone proxy

When you run helm proxy, receipts are exposed as newline-delimited JSON:

curl http://localhost:9090/helm/receipts

The standalone proxy also exposes an in-memory ProofGraph summary:

curl http://localhost:9090/helm/proofgraph | jq .

Fetch receipts from the kernel API

For the full kernel/API surface, list sessions first:

curl http://localhost:8080/api/v1/proofgraph/sessions?limit=10 | jq .

Then fetch receipts for one session:

curl http://localhost:8080/api/v1/proofgraph/sessions/<session_id>/receipts | jq .

You can also fetch one receipt directly by hash:

curl http://localhost:8080/api/v1/proofgraph/receipts/<receipt_hash> | jq .

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CI & release verification

For CI integration (GitHub Actions, GitLab CI), exit codes, and release verification, see Verify & Export.

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Next steps

Goal	Guide
Full verification guide	Verify & Export
Proxy configuration	Proxy API
Understand the pipeline	How HELM Works
Run the full demo	Run the Demo