General software design tips

GunkutA · ‎2020-09-24

Hello guys. I have a general question actually I need suggestions. So I did not want to open a topic for it. I need to make a presentation about a box which will be in some armored vehicle. This box will be like the brain of the vehicle and will control all the sensor datas, GPS values etc that comes in it. This box needs to be safe for MIL-STD-810G 1275 and EMI-EMC. They want me to make some suggestions for them in the presentation (both for software and hardware development). I don't know what kind of suggestions I can give in the software side rather than "use a MCU that support Ethernet and CanBUS" (because they use that communication protocols in the vehicle). So I wanted to take suggestions about it. I need any suggestion that you guys can give. Thanks beforehand.

Cristian Gyorgy · ‎2020-09-24

Hi!

Sorry for being so, but if it's for presentations, the content is usually not important but the looks! Here my suggestions for software:

If the number of bits that go in the CPU does not match the number of bits that come out from the CPU, it will reset!
you encrypt everything to the lowest bit: so, a 1 will be a 0 and a 0 will be a 1, that might be more confusing than AES encription;
any exception will be handled with the following message to the user: "working on it...", as Windows users are accustomed with and will not panic.

As for hardware, just mention it uses Titanium.

:face_with_tears_of_joy: :face_with_tears_of_joy: :face_with_tears_of_joy:

GunkutA · ‎2020-09-24

Hello Christian and thanks for replying to a question that is too general. I was not hoping for any answers!

I have 2 questions related to your suggestions.

1) I think this checking number of bits is an error detection algorith. Communication between ECU's will be only with CANBus, Ethernet and RS422/RS232. I think CANBus uses CRC, Ethernet again uses CRC-32 and I don't know if RS232/RS422 uses any error detection mechanism. So in this case am I right when I say we only need this algorithm for RS232/RS422 or should we use it also in CANBus and Ethernet as an addition to CRC? Also this resetting might make the CPU stuck if there was a collusion or an error I believe?

2) I have no knowledge or experience in encryption unfortunately. Would we need a encryption mechanism for the communication between ECU's in the same vehicle? Make that would make it harder for reverse engineering so it would be a good thing. So my question about that is, what would be the benefit of encryption in here and what is the advantage of using "encryption everything to the lowest bit"?

Thanks again, appreciate it.

Cristian Gyorgy · ‎2020-09-25

Hi GunkutA!

I was just joking, don't take those seriously. ;)

GunkutA · ‎2020-09-25

Ah okay... But still if you have any recommendation about a military software which uses RS232, CANBus and Ethernet, I would appreciate any suggestions. Like putting a Back Up ECU, so if the main ECU fails, we would continue from the Back Up ECU. But I don't know how to make communication between the back up and the main ECU. Should it be CANBus for example? That kind of suggestions. Or how can I make ethernet or canbus or rs232 more robust or safe?