Machine-purchasable data with cryptographic provenance

$ curl -i https://api.clinkforge.com/v1/p/kev-status-by-cve?id=CVE-2021-44228

HTTP/1.1 402 Payment Required
{"x402Version":1,"accepts":[{"scheme":"exact","network":"base","asset":"USDC",
   "maxAmountRequired":"10000","payTo":"0xF3D6…32cc",
   "resource":"…/v1/p/kev-status-by-cve"}],"charged":false}

$ curl -H "X-PAYMENT: $SIGNED" https://api.clinkforge.com/v1/p/kev-status-by-cve?id=CVE-2021-44228

HTTP/1.1 200 OK
{
  "data":        [{ "cve_id":"CVE-2021-44228", "vendor":"Apache", "product":"Log4j2",
                    "date_added":"2021-12-10", "due_date":"2021-12-24" }],
  "provenance":  [{ "authority":"CISA",
                    "source_url":"cisa.gov/…/known_exploited_vulnerabilities.json",
                    "observed_at":"2026-08-24T17:16:58Z",
                    "hash":"13788496…a5f8a9d5" }],
  "attestation": { "signing_key_id":"forge-key-1",
                   "result_digest":"f9e46a11…e0f8dda4",
                   "signature":"G2rw8xom…TIt0CQ==" }
}