Those embarrassing pauses in conversation might be a secret message encrypted and hidden in the silence between words in a Skype conversation
Wojciech Mazurczyk at the Institute of Telecommunications in Warsaw, Poland, has discovered a method to use the silence between words in a Skype conversation. Skype speech is transmitted in 130-bit data packets. But rather than transmitting nothing between words, Skype transmits 70-bit packets that are ignored at the receiving end. Mazurczyk has developed a steganographic method to use these packets, combining both encryption and obfuscation.
Under normal circumstances, the ‘silent’ packets are simply ignored. The receiver — or any eavesdropper — will hear nothing. But Mazurczyk can hijack the packets and inject encrypted data. “The Skype receiver simply ignores the secret-message data, but it can nevertheless be decoded at the other end, the team has found,” reports the New Scientist. “The secret data is indistinguishable from silence-period traffic, so detection of SkypeHide is very difficult,” says Mazurczyk.
Data Can be Hidden in Skype’s Silence | DFI News.