Precise Proofs Js

Read the introduction on Precise-Proofs

Precise Proofs Js is a library for validating fields/leafs from Merkle proofs created with precise-proofs. The library supports 2 hashing functions(SHA2_256SHA3_256) and hex or base base64 encoding for the hashes. Out of the box it uses hex encoding and SHA2_256.

In case you generate your proofs with SHA3_256 and have them base64 encoded. You can switch using the following code:

import {PreciseProofs, SHA3_256} from "precise-proofs-js";

const preciseProofs = new PreciseProofs('base64',SHA3_256);

Supported Proof format

// Sorted Hashes
{
    "property": "valueA",
    "value": "Example",
    "salt": "d555901541825e5d40612d220142c7428c385c48e0245fd3a40b8e3b64679be1",
    "sorted_hashes": [
        "60c3dfcdd85fcef1d4826d4695fb5064aa8434d014f2c1547f9398bdf72bdb75",
        "8951fa82c3f5563d88769a9ecb8f6e03b389c06ff64a1b26dc5898cefe95a42f",
        "46d0a998333fc2c8b4cfff1d5e122f7c32ff46f0a4410f63821f45cc02fd3723"
    ]
}


// Hex with our without the 0x prefix
{
    "property": "valueA",
    "value": "Example",
    "salt": "d555901541825e5d40612d220142c7428c385c48e0245fd3a40b8e3b64679be1",
    "hashes":[
        { "right": "60c3dfcdd85fcef1d4826d4695fb5064aa8434d014f2c1547f9398bdf72bdb75=" },
        { "left": "8951fa82c3f5563d88769a9ecb8f6e03b389c06ff64a1b26dc5898cefe95a42f" },
        { "right": "46d0a998333fc2c8b4cfff1d5e122f7c32ff46f0a4410f63821f45cc02fd3723" }
    ]
}


// Base64 Ecoded
{
    "property":"ValueA",
    "value":"Example",
    "salt":"1VWQFUGCXl1AYS0iAULHQow4XEjgJF/TpAuOO2Rnm+E=",
    "hashes":[
        { "right": "kYXAGhDdPiFMq1ZQMOZiKmSf1S1eHNgJ6BIPSIExOj8=" },
        { "left":" GDgT7Km6NK6k4N/Id4CZXErL3p6clNX7sVnlNyegdG0=" },
        { "right": "qOZzS+YM8t1OfC87zEKgkKz6q0f3wwk5+ed+PR/2cDA=" }
    ]
}

Usage:

import {PreciseProofs} from "precise-proofs";

const rootHash = "29dbffa68e5cd48bb4cb2504190f10883fb187793b2f70eab81fb5440c6809b6";
let proof = {
    "property": "valueA",
    "value": "Example",
    "salt": "d555901541825e5d40612d220142c7428c385c48e0245fd3a40b8e3b64679be1",
    "hashes": [
        "60c3dfcdd85fcef1d4826d4695fb5064aa8434d014f2c1547f9398bdf72bdb75",
        "8951fa82c3f5563d88769a9ecb8f6e03b389c06ff64a1b26dc5898cefe95a42f",
        "46d0a998333fc2c8b4cfff1d5e122f7c32ff46f0a4410f63821f45cc02fd3723"

    ]
}

const preciseProofs = new PreciseProofs();
const valid = preciseProofs.isValidField(proof, rootHash)
// valid  === true


// With base64 encoding
const base64RootHash = "Qpvx6jMpfee4eXYeDm+DO+Z8iArdnYdm3J3BH0AUxHU=";
const base64Proof = {
    "property": "value1",
    "value": "1",
    "salt": "Bs89XQyxE05c57R5KVb8aFk7rqf+A5XUgxlH3t1hRoY=",
    "hashes": [
    {
      "left": "bklbhC4cmgYc+w3k5an7PWICQHNZtozeqD16b7GE5ZI="
    },
    {
      "right": "5hFb4MZvIgE9RQnQDlOGGjahlgDIJwX7Id98oxFECbo="
    },
    {
      "right": "CT59ksUtUWOq+HagFoJgJziPOiHkHlvsvytA6TnTLq8="
    }
    ]
}

const base64PreciseProofs = new PreciseProofs('base64');

const base64Valid = base64PreciseProofs.isValidField(base64Proof, base64RootHash)
// base64Valid  === true

About Transformation Between Compact Property and Literal String of Proof

PropertyTransformHelper can be used to achieve this target First of all, you shoud install protobufjs to generate json definition from proto file.

pbjs example.proto -t json -p "/usr/local/include" -o examples.json

To transform between Compact Property and Literal String, you should provide generated json file and you should provide the package name and the message type defined in proto file.

import {PropertyTransformHelper} from "precise-proofs";
var jsonFormat = require('examples.json');
var helper = new PropertyTransformHelper(jsonFormat,'documents','ExampleDocument', '', []);
helper.compactPropertyToLiteral([3]);
helper.literalToPropertyCompact('value_bytes1')

Missing features

The following features are being worked on:

• construct tree and generate proof