The security of Skype as a missionary communications medium interests me. I wrote about the German authorities difficulty with Skype's encrypted traffic here.
Then yesterday the New York Times had an article discussing the censoring, monitoring and archiving of Skype conversations. For background Skype has developed a client (program you use on your computer) for use in mainland China in cooperation with local telecommunications company TOM. The client, TOM-Skype, sends all of its traffic through TOM where it is censored, monitored and, apparently archived, says a Canadian activist group.
The activists, who are based at Citizen Lab, a research group that focuses on politics and the Internet at the University of Toronto, discovered the surveillance operation last month. They said a cluster of eight message-logging computers in China contained more than a million censored messages. They examined the text messages and reconstructed a list of restricted words.
The list also serves as a filter to restrict text conversations. The encrypted list of words inside the Tom-Skype software blocks the transmission of those words and a copy of the message is sent to a server. The Chinese servers retained personal information about the customers who sent the messages. They also recorded chat conversations between Tom-Skype users and Skype users outside China. The system recorded text messages and Skype caller identification, but did not record the content of Skype voice calls.
I had first heard about this earlier this week when a reader emailed me, cautioning me about Skype use China. The reader mentioned the joint TOM-Skype conversation. In fact, it turns out that this isn't news. The Financial Times ran an article in April of 2006 citing the way TOM censored text messages. Skype commented on that article the same month.
The NYT article is the first to point out, as best I can tell, that that message traffic is both being censored (previously documented) AND archived. In the 2006 FT article Skype's chief executive, Niklas Zennström, said:
“One thing that’s certain is that those things are in no way jeopardising the privacy or the security of any of the users.”
The reality may be quite different. According to the NYT the system is recording the messages and personal information of the users in- and out-side Chine. It does not, apparently, record the content of audio conversations.
This is an interesting development for those of us who may work in politically sensitive environments. While China is probably a bit of an "edge-case" when it comes to government monitoring of telecommunications it is a cautionary tale for all of us.
UPDATE: Skype's president comments on the story here.