Harald Welte wrote: > what is wrong with you (sorry)? No need to apologize, I think you make a very good point.
> The problem with regard to practical GSM A5 cracking is not that > hardware is too expensive or that you need to do your own custom > hardware. > > The problem is that everybody wants a solution / software / ... but > very few people actually are willing to put in the required time, > sit down, get their hands dirty and make it work. I think that there's a lot of excitement because Enemy-of-the-State-like call interception seems to be at the fingertips of the masses, but for most people that would like to try it out, the hardware setup is prohibitively expensive - leading to more or less accurate brainstorming for cheaper solutions. The tradeoff between spending development time on hardware and spending money on USRP is easy with goals such as demonstrating A5/1 brokenness or creating open source GSM software, however not so easy for individuals with anything less than a very strong interest. OsmocomBB is a fantastic development, making consumer electronics usable for open source GSM development and experiments. But it seems to me that it might be(come) difficult to source the relevant hardware which is also problematic, just in another way, for everyone but core contributors. > The state of airprobe's various receivers (tvoid, gsmsp, gsm-receiver) has > only improved marginally throughout the last years. Even today, they are > nothing more than a proof of concept. They're far from what somebody would > want to do actual real-world intercept. They don't even support the various > GSM channel types, they don't contain the neccessarry frequency / gain control > loops for long-time reception, ... > > This has all been clear for years. Work in this area is completely unrelated > to the actual A5/1 cracking and the rainbow tables. There was no dependency > on the rainbow tables needing to be completed before work on the airprobe > receiver code could have been done. That's certainly true. However, without the clear utility for a work, many find it difficult to motivate themselves to produce it. Baby steps basically. But since something very exciting is just around a corner, many are quite eager and want to rush.. > During the same timeframe, a really great Free Software GSM receiver > implementation has been released publicly: That of OpenBTS. Yes! I agree completely. And if there should be any open GSM hardware then I think it must optimize for, and work closely together with OpenBTS. I've spent the last few days reading up and am awed by their progress. > Yet, nobody has lifted a finger and transformed that implementation > (and its contained laurent approximation based demodulation code) > into a new airprobe receiver. I think many if not most have overlooked the significance of airprobe. I certainly have. > But whether you use a USRP2, a USD 20,000 military SDR or a small > custom cheap board will not change the fact that somebody still > needs to write good demodulaton/decoding software. And/or hardware. I think OpenBTS and OsmocomBB are two amazing sources of code, and there is clearly overlap among them and airprobe - or at least there should be! I'm pretty sure that it'd make sense to move some things which are already finished or at least in good condition in both projects into hardware. > And any work spent on new hardware development is not going to > bring any progress to the project. Affordable hardware options mean more people are likely to get involved with open source GSM development in general. True for every other hardware-related open source project I've seen.. > Please focus your scarce resources where it is really needed... Yeah. The focus isn't on PCBs. As you say, this is a software intensive area, the required hardware is "simple". Hardware in hand of course does not bring any software, but already thinking about that hardware helps identify what software to focus on, and next step, hardware availability helps people get involved. //Peter _______________________________________________ A51 mailing list A51@lists.reflextor.com http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
