4. MixCAN Sender

MixCAN sender authenticates data framse based on its configuration. It monitors a set of CAN ids and computes authentication tags for them. It leverages a short term symmetric key (STK) periodically received from the LTK-STK Slave service via MQTT.

4.1. Requirements

• Configured mosquitto MQTT broker

• Configured dias-ltk-stk key manager slave

4.2. Installation

To install mixcan run the script from toolchain/scripts/ :

./mixcan.sh s

The mixcan.service should look like this:

[Unit]
Description=Mixcan Module

[Service]Type=simple
ExecStart=/usr/bin/python3 /usr/lib/python3/dist-packages/mixcan/manager.py -c /etc/mixcan/config.ini
User=pi
Group=pi

[Install]
WantedBy=multi-user.target

And the /etc/mixcan/config.ini should look like this:

[mqtt]
user = mixcan
passwd = mixcan
host = 127.0.0.1
port = 1883

[key]
last_key = /etc/mixcan/keys/last_key.dat

[mixcan]
is_sender = True
frame_id = 0x11 0x12 0x13
mixcan_id =  0x21 0x22 0x23

[pycan]
can =can1

[log]
path = /var/log/mixcan/mixcan.log

where is_sender enables the service to send authenticated frames, frame_id is a sequence of CAN frame ids that are monitored, and mixcan_id is a list with a coresponding set of CAN frame ids authentication tags.