{
  "@context": [
    "https://letterprove.com/ns/attestation/v1",
    "https://schema.org"
  ],
  "id": "att_ledgerly_44fe453b",
  "type": "LetterproveAttestation",
  "schemaVersion": "1.1",
  "attestationKind": "customer-usage",
  "environment": "demonstration",
  "issuer": {
    "name": "Letterprove",
    "id": "did:web:letterprove.com",
    "url": "https://letterprove.com",
    "service": "Independent usage-attestation service"
  },
  "subject": {
    "name": "Ledgerly",
    "domain": "ledgerly.com",
    "url": "https://ledgerly.com",
    "category": "Corporate Card & Spend Management Platform"
  },
  "relationship": {
    "type": "third-party",
    "keyCustody": "In production: segregated, HSM-backed issuer key held arm's-length from the subject. This demonstration uses a demo key.",
    "disclosure": "Letterprove is the independent attestation service; in production it operates arm's-length from the subject with segregated key custody. Participating customers grant read-only, scoped access; Letterprove reads usage counters (seats, activity, tenure) — never customer content — and signs the result. This is a demonstration: the subject and customer identities are illustrative and the signing key is a demo key."
  },
  "issuedAt": "2026-08-06T17:00:00Z",
  "expiresAt": "2026-11-04T17:00:00Z",
  "status": "active",
  "coverage": {
    "customersShown": 8,
    "totalCustomers": 226,
    "shownRepresentTopPercent": 10,
    "percentileMetric": "spend",
    "consentRatePercent": 88,
    "disclosure": "The 8 named customers represent the top 10% of Ledgerly's accounts by spend. 88% of all paying customers consented to independent usage attestation."
  },
  "customers": [
    {
      "company": "Cardinal Trust Bancorp",
      "industry": "Financial Services",
      "plan": "Enterprise",
      "activeSeats": 168,
      "monthsActive": 28,
      "outcome": "-5.4 days monthly close",
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    },
    {
      "company": "Helix Biosciences",
      "industry": "Life Sciences",
      "plan": "Enterprise",
      "activeSeats": 121,
      "monthsActive": 21,
      "outcome": "+$390K annual cash-back",
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    },
    {
      "company": "Atlas Freight Systems",
      "industry": "Logistics & Transportation",
      "plan": "Business",
      "activeSeats": 74,
      "monthsActive": 23,
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    },
    {
      "company": "Everline Insurance Group",
      "industry": "Insurance",
      "plan": "Enterprise",
      "activeSeats": 133,
      "monthsActive": 31,
      "outcome": "-62% out-of-policy spend",
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    },
    {
      "company": "Pinnacle Retail Holdings",
      "industry": "Retail",
      "plan": "Business",
      "activeSeats": 58,
      "monthsActive": 15,
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    },
    {
      "company": "Verdant Energy Partners",
      "industry": "Energy & Utilities",
      "plan": "Enterprise",
      "activeSeats": 104,
      "monthsActive": 24,
      "outcome": "3.9x faster close",
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    },
    {
      "company": "Kestrel Semiconductors",
      "industry": "Manufacturing",
      "plan": "Business",
      "activeSeats": 66,
      "monthsActive": 12,
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    },
    {
      "company": "Summit Public University System",
      "industry": "Higher Education",
      "plan": "Enterprise",
      "activeSeats": 89,
      "monthsActive": 18,
      "outcome": "-41% expense-report cycle time",
      "status": "verified",
      "verifiedVia": "customer-authorized read-only usage attestation"
    }
  ],
  "aggregate": [
    {
      "label": "Annualized spend across attested accounts",
      "value": "$2.3B+"
    },
    {
      "label": "Median tenure of attested customers",
      "value": "22.8 mo"
    },
    {
      "label": "Median policy-compliant spend (attested cohort)",
      "value": "97%"
    }
  ],
  "signatureMeaning": "A valid Ed25519 signature proves this record was issued by Letterprove (key at did:web:letterprove.com) and has not been altered. Each named customer consented and was verified via read-only usage attestation.",
  "methodology": {
    "summary": "Each participating customer grants Letterprove a read-only, scoped token. Letterprove reads usage counters (active seats, activity, tenure) and, where the customer opts in, an outcome metric — never customer content. Figures are canonicalized (RFC 8785 JCS), hashed (SHA-256) and signed with a domain-bound Ed25519 key. The coverage block discloses exactly how representative the shown sample is.",
    "principles": [
      "Named customers consented to be attested.",
      "Read-only usage counters — never customer content.",
      "Coverage percentile disclosed — no cherry-picking hidden.",
      "Signed and independently verifiable — verify, don't trust."
    ]
  },
  "verification": {
    "signatureAlgorithm": "Ed25519",
    "proofType": "JcsEd25519Signature2026",
    "canonicalization": "RFC 8785 JCS (sorted keys, UTF-8, no whitespace)",
    "digestAlgorithm": "SHA-256",
    "didDocumentUrl": "https://letterprove.com/.well-known/did.json",
    "jwksUrl": "https://letterprove.com/.well-known/letterprove/jwks.json",
    "verificationMethod": "did:web:letterprove.com#key-1"
  },
  "proof": {
    "type": "JcsEd25519Signature2026",
    "created": "2026-08-06T17:00:00Z",
    "verificationMethod": "did:web:letterprove.com#key-1",
    "canonicalization": "RFC 8785 JCS (sorted keys, UTF-8, no whitespace)",
    "digestAlgorithm": "SHA-256",
    "digestValue": "W3psbaqgxmuzIHerl-f5tTiOhVd0oUJ_Entq2cfMzjg",
    "signatureAlgorithm": "Ed25519",
    "publicKeyHex": "665ab917d182dc357d33824fcc207e0a5f8a83090d88bb1adaf7e7dc4f9f3ad9",
    "publicKeyMultibase": "z6MkmLosDKtjoyYLqhZFjzqnVMryTbeABj7xbrJb85v2Xfzx",
    "signatureValue": "OhuZFHqP03y96Q8TjSJsivP8ts0BfC5JC5GHGSbWozY7EGcrb6hkIUqrhnPfzC46Rxkc-KKZ1vm68zdSJ_udAg"
  }
}