With regards to stego I am going to give you my expert advice here:
The only one that is accepted by people smarter than I am, and people who live in the shadows, is Outguess.
And the x86 variant. Because neither the RPi version or anything that was ported to macOS will be able to decode the messages. The author of Outguess has made it very clear why his solution is probably the only proper, peer-reviewed and scrutinized version
Outguess was extensively used by Cicada3301