
Phonotactic Reconstruction of Encrypted VoIP Conversations: Hookt on Fon-Iks [pdf] - e12e
http://wwwx.cs.unc.edu/~kzsnow/uploads/8/8/6/2/8862319/foniks-oak11.pdf
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BuildTheRobots
> Abstract—In this work, we unveil new privacy threats against Voice-over-IP
> (VoIP) communications. Although prior work has shown that the interaction of
> variable bit-rate codecs and length-preserving stream ciphers leaks
> information, we show that the threat is more serious than previously
> thought. In particular, we derive approximate transcripts of encrypted VoIP
> conversations by segmenting an observed packet stream into subsequences
> representing individual phonemes and classifying those subsequences by the
> phonemes they encode.

> Drawing on insights from the computational linguistics and speech
> recognition communities, we apply novel techniques for unmasking parts of
> the conversation. We believe our ability to do so underscores the importance
> of designing secure (yet efficient) ways to protect the confidentiality of
> VoIP conversations.

This is a mix of really interesting an quite terrifying. As they say in their
abstract, theoretical attacks have been known for a while but this is
substantially more capable than (I think) anyone ever expected.

