While conspiracy theories abound in all fields, the digital age has added a new playground for the nefarious to up their game. The next time you make a Skype call, you might want to be aware how third-parties could possibly hi-jack your transmission and encrypt a secret message with callers none the wiser.
The technique of "steganography" is known by those in security circles as cryptography's lesser known, less glamorous cousin. Whereas cryptography is the overt use of mathematics to make messages unreadable, steganography relies on stealth and cunning to make them undetectable, by hiding them within otherwise innocent communication.
Steganography use is on the rise, and not just among criminals, hackers, child pornographers, and terrorists. Persecuted citizens and dissidents under authoritarian regimes use it to evade government censorship, and journalists can use it to conceal sources. For those that are addicted to the TV drama hits,The Following on Fox or Homeland on Showtime, these techniques have already been woven into some of the plot lines.
Steganography is an information-smuggling technique—the communication of secret messaging tucked inside a perfectly innocent carrier. The methods are aimed at hiding the very existence of the communication, whereby any unacquainted observer would remain unaware of the presence of the steganographic exchange.
Wojciech MazurczykWojciech Mazurczyk, Maciej Karas and Krzysztof Szczypiorski, are three computer scientists conducting research in this space at the Warsaw University of Technology. For more than a decade since September 11, 2001, stegano.net is a project they incubated to provide innovations in data hiding for existing networks including wireless LANs, Voice over IP (VoIP) and Internet,
Skype is an Internet telephony network based on peer-to-peer architecture. Since its a "closed source," its protocol's specifications are not available to the public, dissimilar to the open sourced social networks of Facebook and Twitter. When the Warsaw University of Technology team turned their focus to Skype, they realized that the service's traffic could easily be used for information hiding.
SkyDe, a contraction of "Skype Hide" was designed exclusively for the purpose of implementing steganography into the process. In layman's terms, SkyDe is based on how to use the Internet phone system to hide communication ironically during periods of silence versus the actual talking.
In most conversations, only one person talks at a time. Yet rather than simply send no data during this unilateral silence, Skype carries on transmitting. Although all of Skype’s data are encrypted, the chunks that encode silence are smaller than those which encode speech, which allows them to be detected reliably. And therein lies the fly in the ointment, and the means to send covert messages.
SkyDe works by encrypting the sensitive data (to make them resemble ordinary, encrypted Skype transmissions) and then waiting for a period of silence to inject them. When it finds one, it hijacks the silent “packets”, as the individual chunks of data sent across the network are called, and replaces their contents with the hidden message. The receiving end then snags the resulting packets and stitches the message back together. Voilà, message delivered with no one but the intended recipient, the wiser.
Now, doesn't the CIA, FBI, Wikileaks and others involved in this type of subterfuge have something to fear? If this technology is now known and written about publicly as I have just done, haven't the beans been spilled? If others know that SkyDe exists, isn't it only a matter of time before encryptors will also be able to find a way to intercept this new use of steganography and retrieive this hidden data? And how much longer before it really goes mainstream and you see it written into the plot line of an upcoming episode of The Following or Homeland?
But for the layman, our worries might be just beginning - as, it's no longer about being careful what you say, it may be more important to be cautious of what you don't say, and how long it takes not to say it! Silence could be golden (for some)!