nowcom (an espnow communications helper for esp32)

nowcom lets you easily send packed + compressed + encrypted data packets to one or all devices in range, and includes replay attack prevention

• packed: you can send most python objects you want; e.g:- obj = [1, 2, 3.14159, {"hello":[b"from",toml.getenv('HOSTNAME')]}]; n.send(obj)
• compressed: if you added #define MICROPY_PY_DEFLATE_COMPRESS (1) to your mpconfigboard.h when you build your micropython firmware, you can set compress=True and you data will be defate.RAW compressed (handy; max packet size is otherwise 234 bytes)
• encrypted: using AES 256
• authentic: packets are hashed with a secret salt to prevent junk-injection attacks
• replay prevention: sequence-state system prevents data replay attacks and works without needing a time or clock. Note that native espnow encryption cannot prevent replay attacks (replay attacks are easy by the way; e.g. $10 usb SDR or anyone else with an esp32 sniffing data)
• broadcast works: you can send one encrypted packet to every device on your network at once, if you like. Note that native espnow encryption cannot do this

How to install

1. Grab the nowcom.py file (or if you are on MicroPython 1.24 the binary nowcom.mpy file)
2. Save the file to your /lib or / folder on your esp32

How to use

import nowcom
n=nowcom.nowcom(debug=True,compress=False,key=b'!AES 16byte key!',salt=b'Any_b""-strInG.HeRe!')
obj = [1, 2, 3.14159, {"hello":[b"from",'HOSTNAME']}]
n.send(obj)        # set tgt=b'somepc' to send only to them
sender,msg=n.recv(wait=1001)  # set tgt=[b'somepc',b'anothr'] to listen only for messages from them

Example

coming soon