KSI JavaScript SDK

Guardtime's KSI Blockchain is an industrial scale blockchain platform that cryptographically ensures data integrity and proves time of existence. The KSI signatures, based on hash chains, link data to this global calendar blockchain. The checkpoints of the blockchain, published in newspapers and electronic media, enable long term integrity of any digital asset without the need to trust any system. There are many applications for KSI, a classical example is signing of any type of logs - system logs, financial transactions, call records, etc. For more, see https://guardtime.com

The KSI JavaScript SDK is a software development kit for developers who want to integrate KSI with their JavaScript based applications and systems. It provides an API for all KSI functionality, including the core functions - signing of data, extending and verifying the signatures.

Installation

In the Browser

To use the SDK in the browser you need the main.js from dist folder, add the following <script> tag to your HTML pages:

<script src="dist/main.js"></script>

In Node.js

To install the SDK for Node.js, use npm package manager:

npm install @guardtime/ksi-js-api

Installing it for using as a library

To use it as a library it is possible to import files from lib/ folder. For that you need following peer dependencies.

npm install @guardtime/common big-integer

Usage

In Node.js:

const fs = require('fs');
const CONFIG = require('../config/ksi-config.js');
const KSI = require('../dist/main.node');

const service = new KSI.KsiService(
    new KSI.SigningService(
        new KSI.SigningServiceProtocol(CONFIG.AGGREGATION_URL),
        new KSI.ServiceCredentials(CONFIG.LOGIN_ID, CONFIG.LOGIN_KEY)
    ),
    new KSI.ExtendingService(
        new KSI.ExtendingServiceProtocol(CONFIG.EXTENDER_URL),
        new KSI.ServiceCredentials(CONFIG.LOGIN_ID, CONFIG.LOGIN_KEY)
    ),
    new KSI.PublicationsFileService(
        new KSI.PublicationsFileServiceProtocol(CONFIG.PUBLICATIONS_FILE_URL),
        new KSI.PublicationsFileFactory(new KSI.BrowserSpkiFactory())
    ));

service.sign(KSI.DataHash.create(KSI.HashAlgorithm.SHA2_256, new Uint8Array(32)))
    .then((signature) => {
        console.log(signature);
    })
    .catch((err) => {
        console.log(err);
    });

fs.readFile('../web/sig.ksig', (_, data) => {
    const stream = new KSI.TlvInputStream(data);
    const tlvTag = stream.readTag();
    const signature = new KSI.KsiSignature(tlvTag);
    service.extend(signature.getAggregationTime())
        .then(calendarHashChain => {
            console.log(calendarHashChain);
        })
        .catch((err) => {
            console.log(err);
        });

    service.getPublicationsFile().then((publicationsFile) => {
        console.log(publicationsFile);

        const policy = new KSI.DefaultVerificationPolicy(new KSI.BrowserSpkiFactory());
        const context = new KSI.VerificationContext(signature);
        context.setPublicationsFile(publicationsFile);
        context.setExtendingAllowed(false);
        context.setKsiService(service);
        policy.verify(context)
            .then((result) => {
                console.log(result);
            })
            .catch((error) => {
                console.log(error);
            })
    }).catch((err) => {
        console.log(err);
    });
});

Development

Install system dependencies:

• Node/npm for development and package management.

Setup project:

git clone git@github.com:guardtime/ksi-js-api.git
cd ksi-js-api
npm install

Add KSI gateway configuration:

cat << EOF > config/ksi-config.js
export default {
  AGGREGATION_URL: 'http://tryout.guardtime.net:8080/gt-signingservice',
  EXTENDER_URL: 'http://tryout-extender.guardtime.net:8081/gt-extendingservice',
  LOGIN_ID: 'CHANGE_ME_KSI_GATEWAY_USERNAME',
  LOGIN_KEY: new Uint8Array([0, 0, 0, 0, 0]),
  PUBLICATIONS_FILE_URL: 'https://verify.guardtime.com/ksi-publications.bin'
};
EOF

Building project:

npm run build

Running tests in node:

npm run test

Running integration tests in node:

npm run integration-test

Documentation

KSI JS SDK documentation is located in /docs folder.

Dependencies

See package.json file.

Contributing

See CONTRIBUTING.md file.

License

See LICENSE file.