Dash Secure Message library

Cryptographic helper functions for use in Dash Platform dapp samples.

Note: this is an experimental library to support dapp sample investigation of Dash Platform usage - not for production use.

Prerequisites

In Node.js:

const DashSecureMessage = require('dash-secure-message');

In the browser:

<script src="dash-secure-message-lib.js" type="text/javascript"></script>

Please see the examples below for sample usage

Browser usage

Include the dash-secure-message-lib.js script file available from the releases page.

Nodejs usage

npm i dash-secure-message

v1.1 experimental features - multiple and binary outputs/inputs

These are currently experimental features and so not included in the generated documentation below, please report any issues or feedback

Multiple inputs and outputs

Multiple public keys can be passed to the Encrypt function recipientPublicKey parameter as an Array. The target message will then by encrypted for each key.

Similarly, multiple messages can be passed to the encryptedMessage parameter of the Decrypt function, which will use a 'brute force' approach to detrmine whether any of the messages can be decrypted by the recipientPrivateKey passed.

The exact return and method signatures depend upon whether the message outputs are encrypted in, or inputs decrypted from, string or binary types, as described below.

Binary input and output

By passing a 4th options parameter to the Encrypt or Decrypt functions, with the property {binary:true}, the messages can be input and output in binary format (a Buffer in nodejs).

A further option {delimiter: <string>} can be passed to override the default double-space delimiter ' ' (or the binary Buffer<20 20>) used for delimiting muliple concatinated buffers when the binary option is used in conjunction with encrypting for multiple target public keys.

The following examples illustrate the use of these options with single and multiple target recipients.

String output (no or empty options passed), muliple public key targets

const encryptedForGroup = DashSecureMessage.encrypt(f2f774d88cd8478eb65a3cd3bba2b74ee235465c4d526cda7c9020c6cda416c4, 'test message', ['A2QdE/f4DIpTuxPkGYFQYzqqZ9ytGy0hMwT6ccth17L4', 'A6+8q1NoaYsmuRNzpoNiUMvDpXEBOYG/yMn3qDXjYNLg'], {});

Returns an Array containing nested Arrays where the first field is the public key passed and the second is the resulting encrypted message e.g.

[
  [
    'A2QdE/f4DIpTuxPkGYFQYzqqZ9ytGy0hMwT6ccth17L4',
    'eyJ0eXBlIjoiQnV ... CwxODZdfQ=='
  ],
  [
    'A6+8q1NoaYsmuRNzpoNiUMvDpXEBOYG/yMn3qDXjYNLg',
    'eyJ0eXB ... cwXX0='
  ]
]

String input of mutiple messages To attempt to decrypt these messages for one corresponding private key, the are passed as a single-dimension Array of encryptedMessages, e.g.

let encryptedGroupMessage = ['eyJ0eXBlIjoiQnV ... CwxODZdfQ==', 'eyJ0eXB ... cwXX0='];
const decrypted = DashSecureMessage.decrypt(privateBob, encryptedGroupMessage, publicAlice, {});

Binary output, muliple public key targets If the {binary:true} option is passed, a single concatenated Buffer is returned (with Buffers of each message delimited by the default Buffer<20 20> or delimiter option if paased). e.g.

const encryptedForGroup = DashSecureMessage.encrypt(f2f774d88cd8478eb65a3cd3bba2b74ee235465c4d526cda7c9020c6cda416c4, 'test message', ['A2QdE/f4DIpTuxPkGYFQYzqqZ9ytGy0hMwT6ccth17L4', 'A6+8q1NoaYsmuRNzpoNiUMvDpXEBOYG/yMn3qDXjYNLg'], {binary:true});

<Buffer 03 a4 4f 95 30 55 63 2c ... 146 more bytes>

Binary input of mutiple messages The single buffer returned above can be paased to the Decrypt function as the encryptedMessage parameter

const decryptedForGroupBob = DashSecureMessage.decrypt(privateBob, <Buffer 03 a4 4f 95 30 55 63 2c ... 146 more bytes>, publicAlice, options);

Any messages which can be decrypted by Bob's private key in this example will be returned in an Array of Arrays, where the first field is the binary value of the encrypted message, and the second field is the string value of the decrypted message, eg

[
  [
    <Buffer 03 a4 4f 95 30 b2 cf 4d 70 35 6a 81 53 f8 46 d9 7f... 47 more bytes>,
    'test'
  ]
]

Documentation

Table of Contents

• DashSecureMessage
  • Examples
• encrypt
  • Parameters
• decrypt
  • Parameters
• hash
  • Parameters
• verify
  • Parameters
• generateEntropy

DashSecureMessage

DashSecureMessage performs ECIES encryption & decryption and Double SHA256 Hashing. Note the class contains only static methods so you do not have to call the contructor, i.e. use DashSecureMessage.encrypt, not new DashSecureMessage()

Examples

<!-- Usage in HTML file -->

<script src="dash-secure-message-lib.js" type="text/javascript"></script>
<script>
const senderPrivateKey = 'e930702ff1dbe78e1d827831e6e29a71264030fbbf5b08154b6cc954aebc011a'
const message = 'hello';
const recipientPublicKey = 'Av1kEA/QGhPA9bP2BlbYrf8RhTqAeU2SdL7OHOXJg/Ve'
const recipientPrivateKey = 'b28aa82d1af0f4548b606897ef376b2035187a70528b203f0604f74f43bc3418'
const senderPublicKey = 'A+KHq0TSgvILh/Bg6eHn7K/y7tvu/uxXjJIRSsqgZlZC'
console.log(`Encrypting message "${message}"...`);
const encrypted = DashSecureMessage.encrypt(senderPrivateKey, message, recipientPublicKey);
console.dir(encrypted);
console.log(`Decrypting result message "${message}"...`);
const decrypted = DashSecureMessage.decrypt(recipientPrivateKey, encrypted, senderPublicKey);
console.dir(decrypted);
console.log(`Hashing message "${message}"...`);
const digest = DashSecureMessage.hash(message);
console.dir(digest);
console.log(`Verifying hash...`);
const verifies = DashSecureMessage.verify(message, digest);
console.dir(verifies)
const entropy = DashSecureMessage.generateEntropy();
console.log(`entropy: ${entropy}`);

</script>

//use in nodejs
const DashSecureMessage = require("dash-secure-message")

const senderPrivateKey = 'e930702ff1dbe78e1d827831e6e29a71264030fbbf5b08154b6cc954aebc011a'
const message = 'hello';
const recipientPublicKey = 'Av1kEA/QGhPA9bP2BlbYrf8RhTqAeU2SdL7OHOXJg/Ve'
const recipientPrivateKey = 'b28aa82d1af0f4548b606897ef376b2035187a70528b203f0604f74f43bc3418'
const senderPublicKey = 'A+KHq0TSgvILh/Bg6eHn7K/y7tvu/uxXjJIRSsqgZlZC'
console.log(`Encrypting message "${message}"...`);
const encrypted = DashSecureMessage.encrypt(senderPrivateKey, message, recipientPublicKey);
console.dir(encrypted);
console.log(`Decrypting result message "${message}"...`);
const decrypted = DashSecureMessage.decrypt(recipientPrivateKey, encrypted, senderPublicKey);
console.dir(decrypted);
console.log(`Hashing message "${message}"...`);
const digest = DashSecureMessage.hash(message);
console.dir(digest);
console.log(`Verifying hash...`);
const verifies = DashSecureMessage.verify(message, digest);
console.dir(verifies)
const entropy = DashSecureMessage.generateEntropy();
console.log(`entropy: ${entropy}`);

encrypt

Parameters

• senderPrivateKey string The private key of the Dash User sending the message
• message string message to encrypt
• recipientPublicKey object The public key for the Identity of the Dash User receiveing the message

Returns string The encrypted message

decrypt

Parameters

• recipientPrivateKey string The private key of the Dash User receiving the message
• encryptedMessage string The encrypted message to decrypt
• senderPublicKey object The public key for the Identity of the Dash User sending the message

Returns string The decrypted message

hash

Parameters

• message string full message to be hashed

Returns string The hex digestof the message

verify

Parameters

• message string full message to be hashed
• digest string digest to compare

generateEntropy

Returns string A dash address fro use as entropy

License

MIT License

Development

To develop this library:

• clone the repository and change to project directory

  git clone https://github.com/dashmachine/dash-secure-message.git && cd dash-secure-message

The source file is src/dash-secure-message.js

• build output

  npm run build

• test with webpack dev server

  npm start

• update documentation (requires npm documentation package installed globally: npm i -g documentation)

Update the Documentation section of the README.md file

npm run docs:readme