Hello There has been some occasional interest in support for encrypted phonecalls on OpenMoko. While I don't probably have the time to majorly contribute to implementing said feature, the matter interests me and therefore a couple of weeks ago I took it upon myself to liaise a bit with GSMK/cryptophone.de, a German encrypted GSM manufacturer. Their CTO Frank Rieger was on holidays, but got back to me recently, in a rather helpful tone.
The cryptophone.de phones use GSM data calls to transmit encrypted voice streams in either direction. This is the most generic suitable method for the Freerunner as well - GPRS lacks the quality of service for decent voip (push-to-talk may be okay), and wifi hotspots aren't always around (plus they don't make you available at your GSM number). Yes, GSM data calls cost per minute and are slow, but they have guaranteed network resources, a decent round-trip, and still enough bandwidth for highly compressed voice streams. As for the cost, it isn't necessarily higher than for voice calls (obviously, this is locale- and operator-dependent and some operators reportedly make you pay through the nose, but that's the way it goes). It would make sense in many ways (security, interoperability, installed base) to use a somewhat proven and already deployed protocol, even if not an open standard (there being none for this purpose I'm aware of). (Disclaimer: I have not personally reviewed the cp.de protocol for security nor am I qualified to do so.) Cryptophone.de makes it clear on their site that their software is non-free and the source is provided for security review purposes only. However, they do also state that they have no problem with somebody else doing their own implementation of the protocol from the spec. I tried in vein to find the protocol documentation on their pages, but after they got back to me, it turns out it's in the source package, in the docs subdirectory. I had been careful not to download that, not to give any impression of unlicensed copying of code. However, if that's what they point to when I specifically ask for specs for the purpose of reimplementation, it should be okay if one doesn't actually cutpaste the code too (personally I wouldn't even look at it, not to inadvertently make similar solutions and cause trouble onwards). You do need to accept a license for the source code and binaries to download the whole package. The download is at the bottom left of http://cryptophone.de/support/downloads/index.html Frank did also mention that they have done some protocol changes "that have been becoming necessary over time"; he expects to have an updated and expanded documentation available by November, and promised to get back to me when that happens. The current docs should probably provide a decent starting point though. (Also of potential interest to some, GSMK are apparently keeping an eye on Linux-based phone development, OpenMoko included, and a product from them wouldn't apparently be out of the question if the market appears.) Soo. Hopefully this information proves useful to some more industrious members of the community, in paving the way for interoperable encrypted calls on OpenMoko. -- Mikko Rauhala - [EMAIL PROTECTED] - <URL:http://www.iki.fi/mjr/> Transhumanist - WTA member - <URL:http://www.transhumanism.org/> Singularitarian - SIAI supporter - <URL:http://www.singinst.org/> _______________________________________________ devel mailing list [email protected] https://lists.openmoko.org/mailman/listinfo/devel
