noise-handshake

Usage

``js
const Noise = require('noise-handshake')
const Cipher = require('noise-handshake/cipher')
const initiator = new Noise('IK', true)
const responder = new Noise('IK', false)

const prologue = Buffer.alloc(0)

// preshared key
initiator.initialise(prologue, responder.s.publicKey)
responder.initialise(prologue)

// -> e, es, s, ss
const message = initiator.send()
responder.recv(message)

// <- e, ee, se
const reply = responder.send()
initiator.recv(reply)

console.log(initiator.complete) // true

// convention is to use rx for
// sending and tx for receiving

// initiator.rx === responder.tx
// responder.rx === initiator.tx

// instantiate a cipher using shared secrets
const send = new Cipher(initiator.tx)
const recieve = new Cipher(responder.rx)

const msg = Buffer.from('hello, world')

const enc = send.encrypt(msg)
console.log(recieve.decrypt(enc)) // hello, world
`

API

#### const peer = new Noise(pattern, initiator, staticKeypair, [opts])

Create a new handshake state for a given pattern. Initiator should be either true or false depending on the role. A preexisting keypair may be passed as staticKeypair

opts may be used to pass in the following:
- curve: module for performing Noise over other curves.
- psk: a 32-byte buffer containing a pre-shared key for patterns containing psk0. (Other psk positions are not currently supported.)

Curve modules should export the following:
`
{
DHLEN,
PKLEN,
SKLEN,
ALG,
generateKeyPair,
dh
}
`

See dh.js for an example.

#### peer.initialise(prologue, remoteStatic)

Initialise the handshake state with a prologue and any preshared keys.

#### const buf = send([payload])

Send the next message in the handshake, add an optional payload buffer to be included in the message, payload is a zero length buffer by default.

#### const payload = peer.recv(buf)

Receive a handshake message from the peer and return the encrypted payload.

#### peer.complete

true or false. Indicates whether rx and tx have been created yet.

When complete, the working handshake state shall be cleared only the following state shall remain on the object:

`js
{
tx, // session key to decrypt messages from remote peer
rx, // session key to encrypt messages to remote peer
rs, // the remote peer's public key,
hash, // a hash of the entire handshake state
}
``

License

Apache-2.0