cryptochat
Encrypted P2P chat over ICMP (Internet Control Message Protocol).
I strongly advise you to pick a high-entropy encryption key to avoid the possibility of brute-force attacks.
Uses raw-socket for ICMP handling and terminal-colors to spice it up a bit.
Install and usage
Make sure you have node 0.10.x
(tip: use n) and then install the package globally with sudo
.
sudo npm install -g cryptochat
Three variants of cryptochat are available depending on your use case:
-
Send and receive messages
$ sudo cryptochat <ip> <encryption_key> -
Receive messages
$ sudo cryptochat server <encryption_key> -
Send messages
$ sudo cryptochat client <ip> <encryption_key>
Because it relies on stdin
for input, it is possible to use pipes to send data:
cat cryptochat.js | sudo cryptochat client <ip> <encryption_key>
ICMP Echo request format
bits 0-7 | bits 8-15 | bits 16-31 |
type = 0x08 |
code = 0x00 |
checksum |
identifier | sequence number | |
payload |
The message data is attached as the ICMP payload.
Message
Messages are piped from stdin
and split into payload packages, which are encrypted and sent as ICMP Echo requests. The payload size per request is currently set to 32 bytes. The first byte is the length of the message and the rest is the message itself.
The first request contains a salt and an initialization vector needed to decrypt the payloads.
byte 0 | bytes 1-15 | bytes 16-31 |
0x3e |
salt | initialization vector |
An "end" request is sent in order for the receiver to know when a message is completed. The end request has the following format:
byte 0 | bytes 1-31 |
0x3e |
0xffffffff... |
When the end request is received, the full message is printed to the screen.
Contribute
As always, contributions are much appreciated.