| 1) What do you do if you're on a Mac? This was prompted by Glenn Fleishman. 2) How would you go about building a wiretap for VoIP. With VoIP that has a link into the Plain Old Telephone System (POTS) there's clearly a choke point that could use traditional wiretap techniques. But it's still made considerably harder by one side of the choke being internet based. Where the VoIP is between computers with no POTS, it's much harder as Voice is just another collection of packets mixed in with the web, email and so on. So that means building logging facilities that understand the protocols which themselves are evolving. The only available choke points are in the ISP so now we're going to have to force the ISPs to put in hardware and software to support the wiretap. This includes large corporates who buy their internet access wholesale. Now what about Voice facilities that are proprietary such as the IM tools and Skype. Your wiretap vendor has a running battle now to keep up with all the various possible protocols some of which are proprietary. 3) Which brings us to Skype. Skype is fully decentralised, P2P and proprietary. How and where exactly would a Skype conversation between two arbitrary endpoints be wiretapped? How would a government agency go about building wiretap facilities for Skype? As if that wasn't hard enough, this is made considerably harder because Skype traffic and setup is encrypted. 4) So the next question is how good is the Skype encryption? Has anyone done any peer analysis and review of Skype's encryption? It's a truism in encryption that security by obscurity doesn't work. The only way to ensure reasonably good encryption is to make the process and technology completely transparent and open. So for example, it's completely useless to use military grade encryption if the key generation or key transfer is done badly or easily guessed. But Skype are probably never going to allow their code to be peer-reviewed which means that we can never know if it's any good. 5) We're beginning to see encryption add ons for things like MSN Messenger and the other IM packages. All the same peer review issues apply. And all the same wiretap issues apply. 6) Almost all the IM systems now have voice capability. But just as their IM functions don't interoperate, their voice functions don't use common standards and they don't interoperate. Unusually, the most surprising was actually MSN Messenger. Up to V4.7 it had a SIP compliant mode that would work with any SIP VoIP system. After that they removed the UI but I think kept the underlying code and now only support specific commercial VoIP-POTS services. MS (and I think the other main IMs) are active in the SIP and SIMPLE standards bodies so why don't they offer it to the end user. 7) Why is SIP and NAT-Firewall configuration so hard for VoIP? The great thing about Skype is that it *just works*. Every other VoIP client I've tried has either been a PITA to configure, or simply didn't work, or depended on a central proxy/relay that is never going to scale. 8) And the big one. Really cheap rate international and national call gateways are starting to appear that piggy back on commodity VoIP systems like IM and Skype. This is going to progressively eat into the Telco's core revenue streams. It seems inevitable that this will become an issue sooner rather than later and Telco's will have to either downsize, shift to a wholesale model or just rely on cellphone charges and cellphone addons like ringtone sales. How long will it be before one or more Telcos get hit *hard* in their bottom line by loss of core business to internet based voice calls? 9) Before the year is out, we'll see combined GSM/CDMA cellphones with a built in WiFi card that can switch relatively seamlessly between cell and WLAN+VoIP access. In the last few years we laughed at journalists writing yet another WLAN vs 3G story. But this could finally kill 3G except for data access in the wild countryside. If I can wait 30 minutes to drive to the nearest Little Chef, Texaco or McDonalds, I can get all the data access and all the free voice calls I need. How long before WLAN hotspots become so widespread that a traveling salesman (and the rest of us) could make that sort of choice? [from: JB Ecademy] |
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[ 26-Apr-04 11:40am ]
