Merkle–Hellman knapsack cryptosystem

The Merkle–Hellman knapsack cryptosystem was one of the earliest public key cryptosystems invented by Ralph Merkle and Martin Hellman in 1978. The ideas behind it are simpler than those involving RSA, and it has been broken. Source: © WikiPedia

Installation

Via npm:

npm i merkle-hellman

via yarn:

yarn add merkle-hellman

⚠️ Attention!

Do not use this system in projects where a cryptographic encryption algorithm is required. The crypto-system is easy to be cracked

Usage

Use Encoder class and encode method for encoding source message

Use Decoder class and decode method for decoding encoded message

Use Cracker class and crack method for getting secret key from public key

Example

Encoding/Decoding messages:

import {
  Decoder,
  Encoder,
} from 'merkle-hellman';

const decoder = new Decoder();
const encoder = new Encoder(decoder.publicKey);

const message = 'Lorem ipsum dolor sit amet.';

const encodedMessage = encoder.encode(message);
const decodedMessage = decoder.decode(encodedMessage);

console.log(`Source message: ${message}`);
console.log(`Encoded message: ${encodedMessage}`);
console.log(`Decoded message: ${decodedMessage}`);

Cracking public key:

import {
  Decoder,
  Cracker,
  Encoder,
} from 'merkle-hellman';

const q = 881;
const r = 588;
const secretKey = [2, 7, 11, 21, 42, 89, 180, 354];
const publicKey = [295, 592, 301, 14, 28, 353, 120, 236];

const originalDecoder = Decoder.from({ secretKey, q, r });
const encoder = new Encoder(originalDecoder.publicKey);
const cracker = new Cracker();

const secretInfo = cracker.crack(originalDecoder.publicKey);

const crackBaseDecoder = Decoder.from(secretInfo);

const message = 'Lorem ipsum dolor sit amet.';

const encodedMessage = encoder.encode(message);
const decodedMessage = crackBaseDecoder.decode(encodedMessage);

console.log(`Source message: ${message}`);
console.log(`Encoded message: ${encodedMessage}`);
console.log(`Decoded message: ${decodedMessage}`);

console.log();

console.log(`Public key: ${publicKey}`);
console.log(`Secret key: ${secretKey}`);
console.log(`Cracked secret key: ${secretInfo.secretKey}`);