A well-known URI for publishing cryptographic posture

Why this exists

QuantaKrypto exists to help organisations move off cryptography a quantum computer will break. Doing that at any scale runs into the same wall immediately: there is no way to ask a deployment what cryptography it runs and get back an answer a machine can check. The inventory has to exist before anything can move, and nothing produces one.

So the survey comes first, and the survey is done by hand. Reading vendor documentation, disclosure notices, changelogs and blog posts, then writing the answer into a spreadsheet that is stale the week after. That work is most of the effort in a migration programme, it does not scale, and it is exactly the part that should be automatable.

The manifest is the smallest thing that would fix it: a predictable location and a schema, so posture becomes something a CI job, an auditor or an agent can fetch rather than something a person has to go and read. It does not need to be clever. security.txt is not clever either, and it works for the same reason.

We hit the same wall again while writing the TLS resumption paper, where a roster of which vendors had switched a feature off still has to be qualified as "last measured or documented". That is corroboration rather than origin: the draft was already filed by then.

What the manifest carries

• posture: a readiness score, whether hybrid post-quantum key exchange is in use, a count of quantum-vulnerable findings by severity, and how many are exposed to harvest-now-decrypt-later.
• cbomSummary: a compact digest of, and a pointer to, the full CycloneDX Cryptography Bill of Materials the summary was derived from. The manifest carries a pointer, not the inventory.
• attestation (optional): a link to a machine-verifiable posture credential. This is what turns a claim into something a third party can check.
• policy: the migration deadlines the project declares it is measured against.

What it deliberately is not

• Not a replacement for CBOM. CycloneDX CBOM is the inventory format that answers what cryptography is in here. The manifest is its public-facing discovery counterpart: a small summary at a predictable URL answering where is this project's posture.
• Not a new cryptographic mechanism, attestation format, or scoring method. It reuses existing pieces and defines only the well-known URI, the media type, and the JSON fields.
• Not closed to extension. The schema deliberately omits additionalProperties: false, and consumers are required to ignore members they do not understand, so the format can grow without breaking readers.

A draft nobody can run is a wish. These are the pieces that exist, stated with their real status rather than their intended one.

• The schema and a worked example, both in quantakrypto/crypto-agility, Apache-2.0.
• A public validator on this site, so a manifest can be checked against the schema without installing anything.
• An emitter in qScan, qscan crypto-agility emit and validate. Honest status: this is on an unmerged branch, not in the published npm package. It is landing, not shipped.
• The survey the draft builds on: crypto-agility as a concept is already well-standardised, and the repository documents which existing work each part reuses rather than reinventing.