Wrapping Documents (Code)

For the current step, you can either opt to use the CLI or Code.

Every TradeTrust document has a checksum that provides it a tamper-proof property. At the same time, because the checksum can be used to uniquely identify a document, the checksum (or its derived value) will be issued into the token registry as evidence of issuance. To compute the checksum, a raw document goes through a process known as wrapping to become a wrapped document. Only then, the document is ready to be issue.

Please note that for Transferable Records, there is NO batch wrapping.

In this guide, we will learn how to generate the checksum by running the wrapping process.

We will use the CLI tool to read all the files in the raw-documents folder, wrap them and then output the files in another directory wrapped-documents.

A merkleRoot, a 64 character long string prepended with 0x will be generated. The merkleRoot is the only information that will be stored onto the Blockchain to verify the issuance status of a TradeTrust document.

Installation

npm i --save @tradetrust-tt/tradetrust-core

---

Usage

Wrapping documents

wrapDocument takes in a documents and returns the wrapped document. Upon validating the document against it's schema, the document hash will be computed, to be placed onto the signature section of the wrapped document. The signature is to be used for integrity verification on the later stage of the tutorial.

import { wrapDocument } from "@tradetrust-tt/tradetrust-core";
const document = {
  id: "SERIAL_NUMBER_123",
  $template: {
    name: "CUSTOM_TEMPLATE",
    type: "EMBEDDED_RENDERER",
    url: "https://localhost:3000/renderer",
  },
  issuers: [
    {
      name: "DEMO STORE",
      tokenRegistry: "0x9178F546D3FF57D7A6352bD61B80cCCD46199C2d",
      identityProof: {
        type: "DNS-TXT",
        location: "tradetrust.io",
      },
    },
  ],
  recipient: {
    name: "John Doe",
  }
} as any;

const wrappedDocument = wrapDocument(document);
console.log(wrappedDocument);

// wrapped Document
{
  "version": "https://schema.openattestation.com/2.0/schema.json",
  "data": {
    "id": "1535e123-172b-477d-be3a-d066ed0066ac:string:SERIAL_NUMBER_123",
    "$template": {
      "name": "da731bd8-455d-4bb7-be2d-52b86e295e14:string:CUSTOM_TEMPLATE",
      "type": "c168dc65-afa4-4051-8c07-3c155c3b37bc:string:EMBEDDED_RENDERER",
      "url": "1a4fd76f-a2aa-4ee9-abb1-3b046aa41b3d:string:https://localhost:3000/renderer"
    },
    "issuers": [
      {
        "name": "2fb102d4-00b2-4c42-87b9-ab545829a4ab:string:DEMO STORE",
        "tokenRegistry": "592202e4-bf4b-4826-9639-a9a3fad38314:string:0x9178F546D3FF57D7A6352bD61B80cCCD46199C2d",
        "identityProof": {
          "type": "a84e9b5b-a99f-4248-ac4d-087b66eec523:string:DNS-TXT",
          "location": "f8bf7139-6ca5-4678-b2c7-49aa81ac3ccc:string:tradetrust.io"
        }
      }
    ],
    "recipient": {
      "name": "c2bab1ae-37d2-4b7a-86c1-f300edc4e6d2:string:John Doe"
    }
  },
  "signature": {
    "type": "SHA3MerkleProof",
    "targetHash": "8dcf358a9436bca6654f565e3c5843d91c0052d3a2eff37bbd380038e8a1fa39",
    "proof": [],
    "merkleRoot": "8dcf358a9436bca6654f565e3c5843d91c0052d3a2eff37bbd380038e8a1fa39"
  }
}

The signature section includes the fields of targetHash and merkleRoot.

signature.targetHash is the generated hash of the document, computed on the algorithm stated on the signature.type.

In the scenerio of wrapDocument, signature.merkleRoot will be the same as signature.targetHash.

Note: Transferable Records are limited to the wrapDocument method. Merkle Root cannot be used to uniquely identified seperate transferable records.

wrapDocument:

• returns an object.
• The object is a wrapped document corresponding to the one provided as input.
• The object has an unique targetHash value based on the input.
• The object has an unique merkleRoot value which correspond to the targetHash.

tip

To extract the merkle root, refer to the example below

const merkleRoot: string = wrappedDocument.signature.targetHash;

Congratulation! you have successfully wrapped the documents, next lets see how we can mint the document to 'issue' it.