# sdcreceipt **Category:** 💻 Developer Tools **Repository:** https://github.com/SemanticDataCharter/sdcreceipt **Views:** 0 **Installs:** 0 **Upvotes:** 0 **Directory Page:** https://allmcps.com/mcp/sdcreceipt ## Description Verify and settle VSL Settlement Receipts. Verification needs no network and no account. ## Claude Desktop Quick Installation Heuristic fallback — verify the package name and runner against the repository README before running it. Uses `npx` (confidence: low): ```json "mcpServers": { "sdcreceipt": { "command": "npx", "args": ["-y","sdcreceipt"] } } ``` ## Documentation & README # sdcreceipt Verify and settle VSL Settlement Receipts. **Verification needs no account, no network, and nothing from the issuer.** That is the point of the tool: a claim that anyone can check a Receipt independently is worth exactly as much as the ability to do it. Apache-2.0. ```bash pip install sdcreceipt ``` ## Four verbs ```bash # Check a Receipt you were sent. Offline. sdcreceipt verify receipt.json --keys issuer-keys.json # Set yourself up as a party: keypair + the document to publish. sdcreceipt init --key-id https://vendor.example/.well-known/vsl-key.json # Authorize a settlement you are a party to. sdcreceipt trigger receipt.json --key vsl-party.pem \ --key-id https://vendor.example/.well-known/vsl-key.json # Ask an issuer for a Receipt. The one verb that needs an account. sdcreceipt settle payload.xml \ --party https://vendor.example/.well-known/vsl-key.json \ --party did:web:partner.example ``` `settle` prompts for anything it needs and was not given, except `current_state`, which defaults to the payload's own ``. It writes the Receipt to `--out` (or stdout), ready for `verify` and `trigger`; `--response FILE` also keeps the issuer's whole answer (the governance decision and the charge). A DENY is issued and signed but accepts no triggers, and `settle` says so. Two of its fields are not guessable and never were: the release condition is hashed by the issuer and never stored, and `current_state`/`target_state` come from a governance workflow defined in a schema the issuer holds, not you. If the issuer refuses the transition it answers with the ones it would have accepted, and `settle` prints them: ``` Governance evaluation produced no Receipt. Decision was DENY From 'draft' you can go to: review This model's workflow: standard: draft -> review -> published ``` It exits 2 there, and 1 on a real failure, so a script can tell "ask again differently" from "something is broken". `verify` exits 0 only if every check passed, so it composes in a shell without anyone parsing output. That is the whole surface. This is a client, not a product, and its value is in being small enough to read. ## Try it without reading anything ```bash python examples/settle.py ``` One settlement end to end: two parties, two signatures, verified offline. No account, no network, no API key. See [`examples/`](https://github.com/SemanticDataCharter/sdcreceipt/blob/HEAD/examples/). ## For an agent Three of the four verbs over MCP, in the same package: ```bash sdcreceipt-mcp --key vsl-party.pem \ --key-id https://vendor.example/.well-known/vsl-key.json ``` Exposes `verify_receipt`, `sign_trigger` and `settle`. Each is advertised only when the server has what it needs, so a tool is never offered whose every call would fail. Two deliberate omissions, and they are the security posture rather than an oversight (see also [SECURITY.md](https://github.com/SemanticDataCharter/sdcreceipt/blob/HEAD/SECURITY.md)): - **No key generation.** A private key generated inside an agent session has no clear custody story. `init` stays a human act at a terminal. - **No submission.** `sign_trigger` returns a signed trigger for you to submit. Submitting takes a destination from the caller, and a signed trigger plus an arbitrary host is the combination worth refusing. `settle` is available when the server is started with `--endpoint` and a token, and it is the only tool that reaches the network. The endpoint is fixed at start-up exactly like the key, so a caller can never redirect where a payload goes. **No tool takes a URL**, and that is the invariant to keep if this ever grows another one. The signing key is given at start-up, never in a tool call, so it does not travel through the conversation. --- ## If you were sent a Receipt You do not need an account with anyone. You need the issuer's published key document and, for a settled Receipt, each party's. The Receipt names the parties by the URIs they publish their keys at; the issuer's key document is at a fixed well-known path. ```bash pip install sdcreceipt curl -O https://sdcstudio.axius-sdc.com/.well-known/sdcstudio-signing-keys.json curl -o vendor-keys.json https://vendor.example/.well-known/vsl-key.json curl -o partner-keys.json https://partner.example/.well-known/did.json sdcreceipt verify receipt.json \ --keys sdcstudio-signing-keys.json --keys vendor-keys.json --keys partner-keys.json ``` Every check is reported, not just the first failure: ``` PASS receipt_hash: matches the canonical content PASS signature[sdcstudio-signing-key-v1]: verifies over receipt_hash PASS trigger[https://vendor.example/.well-known/vsl-key.json]: verifies over {condition_hash, receipt_id} PASS trigger[did:web:partner.example]: verifies over {condition_hash, receipt_id} PASS triggers.unique: one trigger per party PASS settlement.complete: every listed party has triggered VERIFIED ``` With only the issuer's document, the issuer signature and the hashes are checked and `settlement.complete` is recorded as unestablished, so the Receipt does **not** verify: whether every party triggered is a claim about authorization, and no trigger signature was checked. That is the correct answer, not a defect. Pass `--schema settlement-receipt-1.0.schema.json` as well to check the shape first (`pip install 'sdcreceipt[schema]'`). A Receipt carries **hash commitments, never the payload**. So verification tells you a conformant, authorized, dual-triggered exchange occurred, without anyone having to disclose what was exchanged. If you also hold the payload or the governance Receipt, pass them and those get checked too: ```bash sdcreceipt verify receipt.json --keys keys.json \ --payload manifest.xml --governance governance-receipt.json ``` ## If you need to become a party A settlement identifies each party by a `key_id` that **you** control. That is deliberate: it means verifying your signature does not route through the issuer, so nobody has to stay alive for your old signatures to keep meaning something. ```bash sdcreceipt init --key-id https://vendor.example/.well-known/vsl-key.json ``` That writes a private key (mode `0600`) and a key document, and tells you the exact URL the document must be reachable at. Publishing one JSON file is the whole onboarding requirement. Then, when you are sent a Receipt to authorize: ```bash sdcreceipt trigger receipt.json --key vsl-party.pem --key-id ``` It prints a signed trigger and stops. **Signing is inert; submitting is a side effect**, so you send it yourself, or add `--submit `. --- ## ★ Never take the verification key from the document > The set of keys you will accept is decided **before** you read the document, > and the document cannot change it. `ds:RetrievalMethod` in XML-Signature, `jku` and `x5u` in JOSE, and their equivalents elsewhere all say *"here is where my key lives."* That pointer was written by whoever produced the document, so following it asks the document to nominate the key that will judge it. A forged document nominates the forger's key and verification "succeeds." The failure is quiet. A pointer can name a domain that was correct when the document was signed and has since lapsed; anyone who registers it can serve a key at that path, and nothing about the document looks wrong — because nothing about it *is* wrong. The verifier was asked where to look and did as it was told. This tool cannot make that mistake: `verify` takes keys as arguments and has no code path that fetches one. That is a security property, not an inconvenience. The same applies to party keys, with a corollary rather than an exemption. Those `key_id`s *are* URIs the counterparty controls, deliberately. Resolve them over HTTPS only, only for identifiers already recorded in a Receipt you trust, and keep a copy — a party who later loses a domain must not be able to change what their old signatures mean. Supply them, too. Party keys are optional in the sense that the issuer signature and the payload hash can be checked without them, and **not** in the sense that a settled Receipt means anything without them. Whether every party triggered is a claim about authorization, so with no key to check a signature against, `settlement.complete` is recorded as unestablished rather than passed and the Receipt does not verify. Before 4.2.1 it passed on a comparison of `key_id` strings alone, which reported VERIFIED over fabricated triggers. --- ## Conformance `tests/conformance/` ships the issuer's published vectors, and the suite runs this implementation against them. Eleven vectors. **Every invalid one encodes a defect that was actually made**, not a hypothetical: a DER signature where ES256 requires P1363, a signature over the hex text of `receipt_hash` rather than its raw bytes, a governance binding that does not match the evidence held, a trigger replayed from another Receipt sharing the same release condition, and so on. Failing one for the wrong reason does not count — the manifest names the check that must break. ```bash pytest ``` **On independence, honestly.** Passing these vectors shows this tool agrees with the issuer's published expectations, and that it never drifted from them. It is *not* an independent re-derivation: this implementation and the issuer's share design and history. The vectors are most valuable to someone writing a verifier from the specification alone, which is what they are published for. **The canonicalization underneath them is a different case, and it has been checked against an independent implementation.** Every hash in a Receipt is taken over RFC 8785 canonical bytes, so agreement on canonicalization is what the rest of the verification rests on. In September 2026 that agreement was tested in both directions with the MTCP project (Ahmad Abby), which implements RFC 8785 using Trail of Bits `rfc8785` rather than `sdcgovernance`: - MTCP's five published vectors were run against `sdcgovernance.jcs`. Byte-for-byte agreement on the canonical string and on SHA-256, for every vector. The set is a clean regeneration published 9 September 2026, carrying synthetic values in the real schema: `audit_record`, `evaluation_summary`, `score_record`, `sensor_calibration` and `arabic_content`. It **supersedes** the four-vector set of 1 September, and the field carrying the canonical form was renamed from `canonical_hex` to `output`, so a runner written against the earlier set needs updating. - The 21 vectors in `sdcgovernance/test-vectors/rfc8785-canonicalization.json` were run against MTCP's implementation. Zero disagreements, including the edge set: negative zero, subnormals, the 1e21 fixed-to-exponential boundary, C0 controls as lowercase `\u00xx`, unescaped solidus, an astral-plane character, and key ordering across a UTF-16 surrogate pair. - MTCP publishes a conformance run of **19 pure RFC 8785 tests** against the cyberphone Appendix G reference vectors: the six official vectors plus hex verification, ten hard-error rejections (NaN, infinities, integers beyond 2^53, non-JSON types), a number-formatting case, an integer boundary case, and a Node.js differential over 2011 IEEE-754 patterns with zero disagreements. Both sides ran a Node.js differential independently, so the number formatting is checked against the JS engine rather than reimplemented. RFC 8785 §3.2.2.3 adopts ECMAScript `Number::toString` verbatim, which makes the engine the reference for the part that actually goes wrong. Three implementations across two languages, no disagreements. That is not a claim either project could make about itself, and it is the reason to prefer it over a second opinion from the same lineage. It does not make the Receipt vectors above independent. It means that when they disagree with your implementation, the disagreement is about the Receipt rules and not about the bytes underneath them. ## Building your own You do not have to use this tool, and the specification does not depend on it. If you are writing a verifier: **Do not write a second canonicalizer.** Use `sdcgovernance` or another conformant RFC 8785 implementation. A second implementation can disagree with the first, and the disagreement is silent: the bytes differ, so the hash differs, and the artifact reads as tampered with rather than misencoded. This tool re-exports `sdcgovernance.jcs` for exactly that reason and adds nothing. **Refuse rather than guess.** Integers beyond ±(2⁵³−1) cannot round-trip through an IEEE 754 double, and `NaN`/`Infinity` have no JSON representation. Emitting something for those produces a hash that looks fine and fails only in someone else's verifier. **Report every check.** Stopping at the first failure hides the case that matters most: a Receipt whose signature verifies but whose governance binding does not. **Check the curve.** A signature verified against a key on an unexpected curve proves nothing about the party you believe signed. ## Versioning MAJOR tracks the **SDC reference model**, so a `4.x.x` release targets SDC4. It starts at 4 rather than 0 because of that convention, not because there were three earlier versions. MINOR is features, PATCH is fixes. An SDC5 reference model would make this `5.x.x`. The same scheme is used by `sdcvalidator`, `sdcgovernance` and the rest of the family, so a version number tells you which reference model an artifact targets without looking anything up. Note that the **Receipt format version is separate** and independent: a Receipt says `"version": "1.0"`, which is the frozen wire format, not this package. ## Dependencies Python 3.10 or later. Two direct dependencies, both Apache-2.0-compatible libraries: `sdcgovernance` (pinned `>=4.2.0,<5`) for RFC 8785 canonicalization, and `cryptography` for ECDSA. `jsonschema` is optional and only needed for `--schema`. A clean `pip install sdcreceipt` resolves those two plus their own dependencies, about fourteen packages in all; `pip install --report` lists the exact set for your platform. These are **library** dependencies. Nothing here calls a service, and `verify` makes no network request at all. `settle` and `trigger --submit` refuse any endpoint that is not `https://`, except loopback for a local issuer. ## Security See [SECURITY.md](https://github.com/SemanticDataCharter/sdcreceipt/blob/HEAD/SECURITY.md) for how to report a vulnerability, the supported versions, and what this tool does and does not protect against.