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Chapel Hill Computational Linguists Crack Skype Calls

Posted by timothy on from the hookt-on-fon-iks-indeed dept.

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."

9 of 156 comments (clear)

  1. Speach recognition by city · · Score: 3, Insightful

    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?
    1. Re:Speach recognition by drb226 · · Score: 3, Funny
      speach

      Scottish Gaelic. Noun speach f (genitive speacha, plural speachan)
      1. wasp

      Like newcastlejon said, his Scottish Gaelic spelling was flawless. I always hate it when Google doesn't recognize my wasps.

  2. Side channel attack by betterunixthanunix · · Score: 5, Informative

    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
    1. Re:Side channel attack by thePowerOfGrayskull · · Score: 4, Interesting

      There's a reason that SSH has inserted random padding into its packets since its inception. You would think that the folks at Skype might've done just a a bit more research...

    2. Re:Side channel attack by NoSig · · Score: 3, Informative

      If the padding is random you'll decrease the amount of information leaked, but there may still be enough information leaked to reconstruct some conversations. What you really need for total security from this attack is to eliminate the side-channel completely, such as by sending packets of the same size and with the same frequency no matter how much data you've actually got that needs sending. That is a form of padding too, but it is better than random.

  3. Huh? by tthomas48 · · Score: 4, Insightful

    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?

  4. Linguistics not really useful. The ignorance by jmcbain · · Score: 3, Insightful

    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.

  5. Re:Skype's encryption sucks by subreality · · Score: 4, Informative

    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.

    It's actually harder than that. You also have to generate the packets at an even rate as well, or you'll still have some leakage.

    Even after you do that, the presence or absence of a stream of packets will at the very least indicate if a call is in progress; to defend against that, you have to *always* transmit the stream.

    Even then you're leaking information about the maximum amount of data you could be communicating.

    The goalposts keep moving right on down the field when you're talking about side channels. You just have to pick the point where you're comfortable.

  6. Fsck You, Slashdot by theshibboleth · · Score: 3, Interesting

    "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.