Video chat backdoor
Covert backdoors sometimes masquerade as inadvertent defects (bugs) for reasons of plausible deniability.
In some cases these might begin life as an actual bug (inadvertent error), which once discovered are then deliberately left unfixed and undisclosed, whether by a rogue employee for personal advantage, or with C-level executive awareness and oversight.
: "We have not received any subpoenas or court orders asking us to perform a live interception or wiretap of Skype-to-Skype communications.
In any event, because of Skype's peer-to-peer architecture and encryption techniques, Skype would not be able to comply with such a request." CNET asked Microsoft Wednesday morning whether that statement was still correct. It's possible for companies to create communications systems using strong end-to-end encryption believed to be proof against government snoops.
The use of the word trapdoor here clearly coincides with more recent definitions of a backdoor. An example of this sort of backdoor was used as a plot device in the 1983 film War Games, in which the architect of the "WOPR" computer system had inserted a hardcoded password (his dead son's name) which gave the user access to the system, and to undocumented parts of the system (in particular, a video game-like simulation mode and direct interaction with the artificial intelligence).
However, since the advent of public key cryptography the term trapdoor has acquired a different meaning (see trapdoor function), and thus the term "backdoor" is now preferred. Although the number of backdoors in systems using proprietary software (software whose source code is not publicly available) is not widely credited, they are nevertheless frequently exposed.
One document quoted by the newspaper says intelligence analysts began to be able to monitor Skype video calls in July 2012: "The audio portions of these sessions have been processed correctly all along, but without the accompanying video.
Now, analysts will have the complete 'picture.'" This is a dramatic change from Skype's previous apparent resistance to eavesdropping.
They noted a class of active infiltration attacks that use "trapdoor" entry points into the system to bypass security facilities and permit direct access to data. A backdoor in a login system might take the form of a hard coded user and password combination which gives access to the system.Silent Circle, Off-the-Record Messaging for instant messages, and e-mail messages encrypted with PGP do precisely that.But few companies take that step, which can be a significant engineering expense and complicated for customers to use.Another classified document, citing collaboration between NSA and FBI, said: "Feedback indicated that a collected Skype call was very clear and the metadata looked complete.Collaborative teamwork was the key to the successful addition of another provider to the PRISM system." After buying Skype, Microsoft dramatically overhauled its architecture, replacing peer-to-peer "super nodes" with thousands of servers run by Microsoft -- a more centralized approach that may have made it easier for government eavesdroppers.