Skype

• 1 Chinese Skype includes a backdoor
• 2 Microsoft patents technology to wiretap undetected
• 3 All digital voice communication is potentially vulnerable

Because Skype is easy to use and encrypted, it has long been favored by activists for voice communication. Unfortunately, there are a number of troubling questions about Skype. For an alternative, consider trying jingle.

Chinese Skype includes a backdoor¶

From Surveillance of Skype Messages Found in China (this article was written in 2008, when eBay still owned Skype):

A group of Canadian human-rights activists and computer security researchers has discovered a huge surveillance system in China that monitors and archives certain Internet text conversations that include politically charged words. The system tracks text messages sent by customers of Tom-Skype, a joint venture between a Chinese wireless operator and eBay, the Web auctioneer that owns Skype, an online phone and text messaging service.

Skype has defended this publicly, by claiming they are complying with local law.

Microsoft patents technology to wiretap undetected¶

In 2009, Microsoft filed a patent to allow law enforcement the ability to record digital voice communication without detection. In 2011, Microsoft patent 0153809 was approved. It specifically mentions Skype:

…techniques for silently recording telephone communication may not work correctly with VoIP and other network-based communication technology… VoIP may include audio messages transmitted via gaming systems, instant messaging protocols that transmit audio, Skype and Skype-like applications, meeting software, video conferencing software, and the like.

This patent was originally filed long before Skype was purchased by Microsoft, so it is hard to know what to make of it. Regardless, it doesn’t look good for Skype.

All digital voice communication is potentially vulnerable¶

From How to intercept Skype calls

Researchers have discovered a trick that allows encrypted VoIP calls like Skype to be deciphered without the need to crack encryption… Linguists were helped further because the scripts and file sizes of the data sets, even after encryption, matched phonemes. Rules of spoken language mean that phonemes have a strict placement within words, which helped linguists reconstruct conversations.