@appliedblockchain/b-privacy

Summary

B Privacy js library, supported runtimes: nodejs, react-native and browser.

Supports:

• generating new accounts new B({ mnemonic: B.generateMnemonicPhrase() })
• restoring accounts from mnemonic new B({ mnemonic })
• access to mnemonic, private key, public key and ethereum address [a.mnemonic, a.privateKey, a.publicKey, a.address]
• asymmetric encryption a.encrypt(msg, b.publicKey)
• asymmetric decryption b.decrypt(msg, a.publicKey)
• signing a.ecsign(B.keccak256(msg))
• deriving address from public key B.publicKeyToAddress(publicKey)
• See usage for examples

Conventions

We call bytes any byte representation: buffer, hex0x or hex.

bytesTo* family functions convert from one of known byte representations to specified one.

to* family functions will try to convert from any input into desired byte representation, when possible making the same conversions as seen in solidity, ie.:

toBuffer('hello') // returns buffer with utf8 representation of the input string
toBuffer(true) // returns 32 byte, big-endian number 1
toBuffer(false) // returns 32 byte number 0
toBuffer(null) // throws
toBuffer('0x01') // returns one byte buffer
toBuffer('ffff') // returns two byte buffer

Installation

npm i --save @appliedblockchain/b-privacy

Usage

const assert = require('assert')
const B = require('@appliedblockchain/b-privacy')

const simon = new B({ mnemonic: B.generateMnemonicPhrase() })

// sign a message from an account
const helloHash = B.keccak256('hello')
const helloSig = simon.ecsign(helloHash)

// verify that i said hello
const didISayHello = simon.ecverify(helloHash, helloSig)
assert.equal(didISayHello, true)

// anyone can verify i said hello if they have my publicKey or address
const recoveredPublicKey = B.ecrecover(helloHash, helloSig)
assert.equal(recoveredPublicKey, simon.getPublicKey())
const recoveredAddress = B.ecrecoverAddress(helloHash, helloSig)
assert.equal(recoveredAddress, simon.address)

const mike = new B({ mnemonic: B.generateMnemonicPhrase() })
const hiMike = simon.encrypt({
  message: 'hello',
  another: 'key'
}, mike.publicKey)

const mikesMessage = mike.decrypt(hiMike, simon.publicKey)
assert.deepEqual(mikesMessage, { message: 'hello', another: 'key' })

const helloEveryone = { hello: 'everyone!' }
const [ sharedBlob, readerBlob ] = simon.encryptShared(helloEveryone)

// i can decrypt my own shared message, other people can't without calling shareSecret
assert.deepEqual(simon.decryptShared(sharedBlob, readerBlob), helloEveryone)

// providing a mnemonic is optional, if nothing provided then one will be generated
const bob = new B()
const bobReaderBlob = simon.shareSecret(readerBlob, bob.publicKey)

// bob can now decrypt the shared message
const bobsMessage = bob.decryptShared(sharedBlob, bobReaderBlob)
assert.deepEqual(bobsMessage, helloEveryone)

// bob can now pass the message on securely
const alice = new B()
const aliceReaderBlob = bob.shareSecret(bobReaderBlob, alice.publicKey)

const alicesMessage = alice.decryptShared(sharedBlob, aliceReaderBlob)
assert.deepEqual(alicesMessage, helloEveryone)

For more usage examples please refer to tests in test directory.

---

We'll need to clean-up below docs

Blockchain Privacy JS library

Provides an easy way to interact with keys and sign messages (note: storage of keys should be handled outside this library)

Development

npm run dev

Build

Package the library for release (browser/node)

npm run build

Testing

npm test

or:

npm i -g jest

jest

Browser Usage

Please require dist/b-privacy.js, that's the browser-ready version.

You also need to include bitcore-lib manually before that. See test/browser.index.html for a working example.

To make the example work you need to build bitcore-lib for the browser, run:

cd node_modules/bitcore-lib
npm i
gulp browser