No, you are right. Posting the information is not illegal. If you watch the lecture I reference in the tutorial he discusses some of the legalities around releasing information that could compromise an active communications system that contains personal information and/or is being used by law enforcement and safety personal. In fact that is why no information was released in 2007 (might be off on the year) from the group that was researching GSM decryption at the time. Eventually, as we all know, it came out. So it isn't an issue to post tutorials on the use of kraken or the rainbow tables.
The gray area comes in when it is new information that could put people at risk. Therefore the project I am in process of conceptualizing, using USRP/SDR to capture and decrypt GSM signals live, would have to be something that a private and select group of individuals worked on with me. That project has a long way to go before it even leaves the theoretical stage, but I assure you, at some point it will.
By the way excellent analogy! I would like to focus on providing support for this tutorial right now, as I am sure as people run through it in different environments with different variables different complications may arise. I really want to see everyone functioning at 100% with Kali and GSM, it has been too long since this has functioned, and it appears even then, airprobe never really worked quite right within Kali.
On a side note, I am very excited, the creator of GR-GSM has contacted Slick and I and wants to go over the tutorial. He said he gets a lot of questions about Kali and GR-GSM, and wants to see if this works. Hopefully this tutorial can help Kali and its users get back in the running in the SDR community as a competitive distro, and the best!
Short answer, yes, we will cover decryption in the near future. It appears there is a demand, and I do love to write the tutorials!
