#!/usr/bin/env python3
from binascii import hexlify
from binascii import unhexlify
import socket


# from curve25519 import Private, Public
import nacl.secret
import hmac
import hashlib

SERVER = ('mitm.ctfcompetition.com', 1337)
p = (2 ** 255) - 19


def ReadLine(reader):
  data = b''
  while not data.endswith(b'\n'):
    cur = reader.recv(1)
    data += cur
    if cur == b'':
      return data
  return data[:-1]


def WriteLine(writer, msg):
  writer.send(msg + b'\n')


def ReadBin(reader):
  return unhexlify(ReadLine(reader))


def WriteBin(writer, data):
  WriteLine(writer, hexlify(data))

my_key = (p-1).to_bytes(255, 'little').rstrip(b'\x00')

ss = socket.socket()
cs = socket.socket()
ss.connect(SERVER)
cs.connect(SERVER)

WriteLine(ss, b's')
WriteLine(cs, b'c')

server_public_key = ReadBin(ss)
server_nonce = ReadBin(ss)

client_public_key = ReadBin(cs)
client_nonce = ReadBin(cs)

print(my_key)

print(server_public_key, server_nonce)
print(client_public_key, client_nonce)

WriteBin(ss, my_key)
WriteBin(ss, client_nonce)

WriteBin(cs, my_key)
WriteBin(cs, server_nonce)

server_proof = ReadBin(ss)
client_proof = ReadBin(cs)

print(server_proof)
print(client_proof)

WriteBin(cs, server_proof)
WriteBin(ss, client_proof)

auth_data = ReadBin(ss)
print(auth_data)

WriteBin(cs, auth_data)

print(ReadLine(cs))

mySecretBox = nacl.secret.SecretBox(my_key)
print(mySecretBox.decrypt(auth_data))

ss.close()
cs.close()