noiseprotocol 0.2.2

Basic usage

NoiseConnection class provides highest level of abstraction for the package. You can access full functionality of the package through this class’ interfaces. An example for setting up NoiseConnection could look like this:

import socket

from noise.connection import NoiseConnection

sock = socket.socket()
sock.connect(('localhost', 2000))

# Create instance of NoiseConnection, set up to use NN handshake pattern, Curve25519 for
# elliptic curve keypair, ChaCha20Poly1305 as cipher function and SHA256 for hashing.
proto = NoiseConnection.from_name(b'Noise_NN_25519_ChaChaPoly_SHA256')

# Set role in this connection as initiator
proto.set_as_initiator()
# Enter handshake mode
proto.start_handshake()

# Perform handshake - as we are the initiator, we need to generate first message.
# We don't provide any payload (although we could, but it would be cleartext for this pattern).
message = proto.write_message()
# Send the message to the responder - you may simply use sockets or any other way
# to exchange bytes between communicating parties.
sock.sendall(message)
# Receive the message from the responder
received = sock.recv(2048)
# Feed the received message into noise
payload = proto.read_message(received)

# As of now, the handshake should be finished (as we are using NN pattern).
# Any further calls to write_message or read_message would raise NoiseHandshakeError exception.
# We can use encrypt/decrypt methods of NoiseConnection now for encryption and decryption of messages.
encrypted_message = proto.encrypt(b'This is an example payload')
sock.sendall(encrypted_message)

ciphertext = sock.recv(2048)
plaintext = proto.decrypt(ciphertext)
print(plaintext)

The example above covers the connection from the initiator’s (“client”) point of view. The snippet below is an example of responder’s code (“server”) using a socket connection to send and receive ciphertext.

import socket
from itertools import cycle

from noise.connection import NoiseConnection

if __name__ == '__main__':
    s = socket.socket()
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.bind(('localhost', 2000))
    s.listen(1)

    conn, addr = s.accept()
    print('Accepted connection from', addr)

    noise = NoiseConnection.from_name(b'Noise_NN_25519_ChaChaPoly_SHA256')
    noise.set_as_responder()
    noise.start_handshake()

    # Perform handshake. Break when finished
    for action in cycle(['receive', 'send']):
        if noise.handshake_finished:
            break
        elif action == 'send':
            ciphertext = noise.write_message()
            conn.sendall(ciphertext)
        elif action == 'receive':
            data = conn.recv(2048)
            plaintext = noise.read_message(data)

    # Endless loop "echoing" received data
    while True:
        data = conn.recv(2048)
        if not data:
            break
        received = noise.decrypt(data)
        conn.sendall(noise.encrypt(received))

Wireguard integration example

In examples directory, there is an example of interoperation of this package with Wireguard VPN solution. Please refer to README.md of that example for details.