[security] Introducing signing support to MySensors

[noelgeorgi]

@Anticimex said:

@noelgeorgi AES encryption is already supported for both NRF24 and RFM69 radios. See MyConfig.h on the development branch for the flag to use. Doyxgen documentation I link to in this thread on the topic post also contain the personalization instructions for encryption on the development branch.

Thanks for the info.
I'm getting the following errors when compiling securitypersonalizer:

Arduino: 1.6.7 (Linux), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"

/home/technoman/Arduino/libraries/MySensors/examples/SecurityPersonalizer/SecurityPersonalizer.ino:83:28: fatal error: sha204_library.h: No such file or directory
 #include <sha204_library.h>
                            ^
compilation terminated.
exit status 1
Error compiling.

  This report would have more information with
  "Show verbose output during compilation"
  enabled in File > Preferences.

doesnt the ATSHA204 library has ATSHA204.h

[Anticimex]

@noelgeorgi master or development branch?

[noelgeorgi]

@Anticimex development branch

[Anticimex]

@noelgeorgi have you made changes to the sketch? Jenkins builds it without problems.

[noelgeorgi]

@Anticimex no, I'm using the sketch from the examples.....:confused:
am i missing some libraries????

[Anticimex]

@noelgeorgi if you have cloned the arduino git you have everything you need. I can build that sketch myself and have used it many times. I suspect you have a problem with your environment if you get compilation errors in it. We continously test the repository and build all examples nightly to make sure it all works as it is supposed to. You can see this at ci.mysensors.org

[noelgeorgi]

@Anticimex sorry for the interruption, i was using rsync to get eveything synced and i might have messed something uop, sha204 library was missing from my libraries folder, now everything works, thanks for the prompt and fast support.

[Anticimex]

:thumbsup:

[TD22057]

@Anticimex - thanks for this. I finally got around to enabling signing on everything while I was testing out my new board design. I followed your schematic from your board design when I built mine and I just went through the instructions to configure the crypto chip and everything went smoothly. Thanks for the work and the good instructions!

[Anticimex]

@TD22057 that's really nice to hear! Are you using a stable release or the development/beta channel?

[TD22057]

@Anticimex
I used the signing sketch on the dev branch - I'm in the process of shifting my stuff over to the dev branch from 1.5 now.

[Anticimex]

Ok, cool. As you might have noticed, personalization has changed a bit on development. Also, whitelisting works slightly differently/better.

[Pierre P]

Isn't blacklisting cool too to use ?
Like, if we know the "name" of the sensor lost, we push it to the black list and voila ? This way, we don't have to put a long list a agreed sensors if we have only two nodes outside the house.
... I think.

[Anticimex]

@Pierre-P because if a node is lost, you no longer control that node. So anyone could reprogram it to have it identify itself in any way possible. We have to assume an attacker has full source code access, so they can rewrite the signing algorithm to use a fake serial as salt for the signature to trick the GW to believe it is a new node. A whitelist mean the attacker has to know the ID/serial of one of the nodes you trust. Which they won't know unless they can get access to that node.

[Pierre P]

Thanks for the complet answer !

[Anticimex]

@Pierre-P you are welcome. Security is best when it is totally open and the implementation is aware of this. That makes it quite difficult to circumvent, and it also allows to be challenged. That way, with many eyes examining it, it gets stronger and stronger :) I welcome all attempts to crack it. White or black hat style.

[Soloam]

Hello all! What would require less flash memory? Signing by ATSHA204A Chip or by software?

[Anticimex]

Signing by ATSHA204A require less flash memory, but takes longer to execute (at least on 8MHz AtMega328).

[Soloam]

@Anticimex assumed that, but this post on the forum got me confused: http://forum.mysensors.org/topic/2005/software-aes-encryption-for-nrf24/19

According to that post, he uses software on the SenseBender with Encryption because, according to him "...encryption and ATSHA204A is to big for the SenseBender... ".

I would like to add Signing and encryption to my nodes, but I don't know if it will fit on my Atmega328 flash!

[Anticimex]

Well, how much space you have depend on your sketch and on the features you enable in the library, so it is impossible to predict how your code will fit. I suggest you just try to enable what you want and compile, and you'll know :)