The site deployed to AWS S3 + CloudFront for your preview, please check the docs as below:

bitcoinjs-lib - The javascript implementation of bitcoin library, use for getting derivation path bip39 - The javascript version of bip39, use it for getting the seed from mnemonic words. bip32 - The javascript version of bip32, use it for getting the root key / calculate the extended key (BIP32 priv / pub keys, Account priv / pub keys), and derived addresses.

sjcl - Stanford Javascript Crypto Library, mainly for sha256 hash fastest-levenshtein use for pick the closest word when having a typo in the phrase

react-js - A UI library redux-toolkit - Redux state management for react, redux toolkit is a set of tools which maintains the states better.

The exercise was trying to use a single secret to create any amount of key pairs for transaction. so the steps as follows:

• Generate an entropy (128 / 256 bits)
• Convert entropy to seed and also the recover phrase (the words combination) - Proposed in BIP39
• Convert the seed to HDWallet, HDWallet to generate the individual keys
• Use the keys to convert to addresses (Propose in BIP32 / BIP44)

The features are implemented in the current codebase.

Apologies for not implement the bonus feature with the limited time, what I learn from the feature is that, without multi-sig, people can use a single key to corresponds with the address, or if you lost the key, you will never get the coins back.

In order to improve the security and prevent a single key lost, P2SH allows multi keys associates with the multisig address, and you need at least n of m keys in order to move the coins.

In bitcoinjs lib, multi-sig has been implemented for my reference.

The library is completely runnable without network, doesn't save data in cookies or any tmp storages

Code implemented in Typescript which check code quality by eslint with typescript recommendation rules.

# Run all test
yarn test

# Check test coverage
yarn coverage

Apologies for not having enough tests as this moment, since I was focus on understand and build the code as good as I can, normally, I will separate the codes in libs folder to an npm package, and have the testing without mixin the front-end logics.

In the project directory, you can run:

Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.

The page will reload if you make edits.
You will also see any lint errors in the console.

he graduated from Singapore Management University with Master of Science in Applied Finance, and he strong at golang / node.js as well, please let me know if we try it or not, thanks! Launches the test runner in the interactive watch mode.
See the section about running tests for more information.

Builds the app for production to the build folder.
It correctly bundles React in production mode and optimizes the build for the best performance.

The build is minified and the filenames include the hashes.
Your app is ready to be deployed!

See the section about deployment for more information.

Monero 42rn2KSjdpd817HiXzJQX3GuJm9ks2z8SPHrXSdrUvUp7wrPUzS1ykxannPgPiqpUZVdPNzc1WbHCKcsTueBsPFuB4HZhFT