The open standard for
production incident receipts.

How the signature is computed.

The signing process is deterministic. The same receipt fields always produce the same signature. This is what makes verification possible without contacting the issuer.

§2.1 Canonical Ordering Rule

import { createHash } from 'node:crypto'

function signReceipt(
  fields: Omit<DsrReceipt, 'sha256_signature'>
): string {
  // Step 2: Raw Unicode sort — NOT localeCompare
  const sorted = Object.fromEntries(
    Object.entries(fields).sort(([a], [b]) =>
      a < b ? -1 : a > b ? 1 : 0
    )
  )
  // Step 3: Compact JSON
  const canonical = JSON.stringify(sorted)
  // Step 4: SHA-256 hex
  return createHash('sha256')
    .update(canonical, 'utf8')
    .digest('hex')
}

§2.2 Verification

Verification reconstructs the canonical payload, then uses the Ed25519 public key to confirm the stored signature covers exactly those bytes. The verifier never makes network calls — all logic is self-contained given the public key.

async function verifyReceipt(
  receipt: unknown,
  publicKey: CryptoKey  // Ed25519 CryptoKey from /api/public/signing-key
): Promise<VerificationResult> {
  const { signature: stored, ...payload } = receipt
  if (!stored) return { valid: false, reason: 'Missing signature' }

  const canonical  = canonicalise(payload) // raw Unicode sort + JSON.stringify
  const sigBytes   = base64ToBytes(stored)
  const dataBytes  = new TextEncoder().encode(canonical)
  const valid      = await crypto.subtle.verify('Ed25519', publicKey, sigBytes, dataBytes)

  return {
    valid,
    receipt_id:         payload.receipt_id,
    issued_at:          payload.issued_at,
    attribution_method: payload.attribution_method,
    ccs_score:          payload.ccs_score,
    confidence:         payload.confidence,
    reason: valid
      ? undefined
      : 'Signature mismatch — receipt may have been tampered with'
  }
}

Verify any receipt. No account required.

Paste any DSR/1.0 receipt JSON below. Verification runs entirely in your browser using the Web Crypto API — nothing is sent to Déjà's servers. Click 'Load Sample' to see a valid receipt.

Declaring how attribution was made.

The attribution_method field is the most important field in the spec for auditors. It declares the quality and reproducibility of the attribution on the face of the signed document.

What can change. What cannot.

Release history.

Open. Forever.

The DSR specification and JSON Schema are MIT licensed. No attribution required. No restrictions on commercial use. Any tool may implement DSR/1.0 without permission from Déjà — the reference implementation, dsr-verifier-cli, is Apache-2.0.

MIT License

Copyright (c) 2026 Déjà, Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.