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Chapel Hill Computational Linguists Crack Skype Calls
mikejuk writes "You might think of linguistics as being interesting but not really useful. Now computational linguistics [PDF of original paper] has been used to crack Skype encryption and reconstruct what is being said in a VoIP call. What is surprising is that though they are encrypted, the frames that make up a Skype call contain clues about what phonemes are being spoken."
My Google Voice voicemail transcription gets about 1 out of 4 words correct. Can Google please buy this company already.
I am a v1ral sig. Plse c0py me and h3lp me spread. Thank y0u?
The wording in TFS is a little misleading; they did not "crack Skype encryption," they found an exploitable side channel in Skype. The crypto itself has not been cracked, but it was being used in a way that leaked lots of information.
Palm trees and 8
Of course, since the data basically represents sound waves, there is a certain level of predictability and pattern on the data unlike normal data which is much more random.
It would have to be a special encryption to get rid of this pattern using a more dynamic algorithm that changes as it progress (which can make it annoying to decrypt or simpler to detect) or disjoint the data over a greater amount of data (making it somewhat harder to find the patterns though still might be possible) of the encryption though that is difficult in a time sensitive app like Skype which encrypts and sends as it receives the data.
I remember reading something similar with sip over encrypted channel... I guess it is the plague of all compressed communication even if encrypted... the only way to bypass that is use an uncompressed protocol and not blank out the silence. I guess what's new is they've done it with skype.
Never antropomorphize computers, they do not like that
The reason why is that any serious encryption attempt of IP traffic would make all packets a constant size, significantly below expected MTU size (taking into account tunnels). This attack would not exist in that scenario. They are measuring the payload size of IP packets and matching it to phonemes spoken.
I probably shouldn't blame them for this, but it's barely worth the effort of encrypting the traffic if it is this easy to sniff out the words being spoken.
HBI's Law: Frequency of calling others Nazis is directly correlated with the likelihood of the accuser being Communist.
No, I find linguistics pretty useful. Especially since it has some pretty 1:1 relationships with computer programming. And Larry Wall was a linguist. And what kind of lead in is that?
A December 2010 paper, "Uncovering Spoken Phrases in Encrypted Voice over IP Conversations", takes a similar approach.
The article was published in ACM Transactions on Information and System Security, PDF version.
The paper details a gap in the security of VBR compressed encrypted VoIP streams. The authors had earlier found that it is possible to determine the language that is spoken on such a VoIP call, based on packet lengths. Now they have expanded their research and show that itâ(TM)s possible to detect entire spoken phrases during a VoIP call. On average, their method achieved recall of 50% and precision of 51% for a wide variety of phrases spoken by a diverse collection of speakers (some phrases are easier to detect than others; the recall various from 0% to 98%, depending on length of the phrase and the speaker). In other words: they can detect fairly well if a certain phrase is being used in a conversation, even though the VoIP conversation is encrypted.
The ignorance of the statement "You might think of linguistics as being interesting but not really useful" is simply astounding. Linguistics provides the foundation and formal frameworks for grammar, syntax, morphology, phonetics, and semantics that allows us to better understand language. From that basis, computational linguistics is seen simply as an application of linguistics, and computational linguistics of course leads to information retrieval, automatic speech recognition, text classification, and other fields that are among the most important computing topics of the 21st century. Ignorantly saying linguistics is interesting but not useful is like saying physics and chemistry are interesting but not useful.
It's hardly "newly rich" - it's been rich for quite some time. I'd call this more a "desperate grab for relevance".
which is totally what she said
Yes; this is follow-up work to the paper in that earlier article.
Also important to note, neither paper is specific to Skype; their work is on encrypted VoIP in general. But apparently /. prefers things having to do with Skype for some reason.
"You might think of linguistics as being interesting but not really useful" Way to go Slashdot, insult one of the most important fields in existence. Do the editors and readers really not realize how closely comp ling is related to AI? I have confidence that eventually computational linguistics will crack speech/language in general and lead to computers that can learn languages as readily as human infants. This will be momentous because it would allow communication between computers and humans. Now it wouldn't solve the consciousness problem, but it would be a step in the right direction.
Okay, so, then, what are the teachers in the Charlie Brown specials saying?
Huh? Mr. Smarty-pants?