Re:Data.sparkfun.com: A place to push your data
by simcop2387 on Thursday July 10, 2014 @06:44PM
(#8017819)
Signing might be doable like that but it all depends on the size of the data that you're pushing. if it's a long string of readings that might not be so easy since you might not be able to fit everything in memory still (These devices routinely have <4k of ram). Might be doable to go byte by byte as you build the message and output it. It's certainly a challenging problem.
Re:Data.sparkfun.com: A place to push your data
by tdicola on Thursday July 10, 2014 @07:03PM
(#8017889)
Yep the libraries I've used can generate a hash byte by byte luckily without loading everything in memory. Here's an example of how I call Amazon services and generate a signature on an Arduino: https://github.com/tdicola/CloudThermometer
Yeah no SSL support on Arduino-capable hardware is a bummer. I have been able to do Amazon's signature generation on an Arduino without too much trouble though (just need to run SHA256 hash algorithm a few times). I would definitely think about key revocation and renewal since folks will need it if someone steals their keys.