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NSA Able To Crack A5/1 Cellphone Crypto

jones_supa writes "The most widely used cellphone encryption cipher A5/1 can be easily defeated by the National Security Agency, an internal document shows. This gives the agency the means to intercept most of the billions of calls and texts that travel over radiowaves every day, even when the agency would not have the encryption key. Encryption experts have long known the cipher to be weak and have urged providers to upgrade to newer systems. Consequently it is also suggested that other nations likely have the same cracking capability through their own intelligence services. The vulnerability outlined in the NSA document concerns encryption developed in the 1980s but still used widely by cellphones that rely on 2G GSM. It is unclear if the agency may also be able to decode newer forms of encryption, such as those covered under CDMA."

15 of 122 comments (clear)

  1. This is why... by Anonymous Coward · · Score: 5, Funny

    I only speak in Navajo.

  2. Don't Worry they Built it that Way by Anonymous Coward · · Score: 5, Insightful

    The NSA has maintained a policy that any encryption that was able to block their efforts was ILLEGAL in the USA. Do you actually expect anything to work? Bluntly do you expect to have your banking transactions secure when they can crack them. How about your phone call confirmations when they can record them and appear to be you. How about a hacker who walks into the NSA back-door in all of this. This makes the NSA the biggest terrorist and criminal agents in the world and the accomplace to the stunningly biggest crime situation in history where nobody is secure!

  3. And this is news? by Anonymous Coward · · Score: 5, Informative

    Hardly rocket science these days, see e.g.https://srlabs.de/decrypting_gsm/

    1. Re: And this is news? by Joce640k · · Score: 4, Informative

      A5 has been broken for *years*.

      (Since 1994 according to wikipedia: https://en.wikipedia.org/wiki/A5/1#Security , with many improved attacks since then)

      So this is hardly "news" ... but it's good to keep shining bright lights on the NSA to keep them scurrying.

      --
      No sig today...
  4. If you don't like them hearing your private speech by Toe,+The · · Score: 3, Insightful

    Well then, just self-censor. Isn't that the road we're heading down?

  5. So what? by Guppy06 · · Score: 5, Insightful

    My mobile carrier is AT&T. The NSA doesn't need to break the encryption.

    1. Re:So what? by tulcod · · Score: 4, Informative

      FYI, in usual radio communication, what flies through the air are not electrons but photons. These photons are generated by wiggling a few electrons back and forth at the transmitter, and this in turn wiggles a few electrons back and forth on the receiving end.

  6. Re:If you don't like them hearing your private spe by Anonymous Coward · · Score: 3, Interesting

    It isn't a private speech. You have no reasonable expectation of privacy because it is now widely known that the government spies on our communications. Therefore, it is not reasonable to have an expectation of privacy.

    Man, the courts really screwed up when they called it an "expectation of privacy".

  7. Hysterics by squiggleslash · · Score: 4, Interesting

    1. A5/1 is the "insecure, intended for export" cipher. Any US or European operator that uses it is not following recommendations.
    2. It was cracked in the early 1990s. It would be bizarre if the NSA didn't know how to read it. Like I said, it was never intended to be secure by its creators. As in - GCHQ, the NSA's UK ally, has ALWAYS known how to crack it.
    3. One problem with intercepting a GSM mobile call would be dealing with the fact that, as soon as you move away from the transmitting device, you're having to deal with interference from neighboring cells. Which is why any intelligence agency worth its salt isn't going to do that terribly often. What they'd do is install the tap on the operator's network.

    So, in short, this article is claiming the NSA "can do" something, but only in non-Western countries, that it's unlikely to need to do given the fact the alternatives are way easier, and that we know it "can do" anyway, and knew it in the mid-1990s, and probably figured it could do right from the beginning given the close relationship between the NSA and CCHQ. This is news... why?

    --
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    1. Re:Hysterics by cianduffy · · Score: 5, Informative

      A5/1 is not the export cipher - that's A5/2.

  8. Can you hear me now? by Sponge+Bath · · Score: 3, Funny

    Loud and clear. All your phone calls are belong to us.

  9. Thst's 14 year old news by ei4anb · · Score: 4, Informative
    It has been common knowledge for at least 14 years that governments could eavesdrop on A5/1 traffic http://cryptome.org/gsm-joke.htm

    Many governments have warned industrialists not to discuss secrets when using a mobile phone near the country borders. Only the radio channels are encrypted in GSM, lawful interception happens on the wired network that interconnects the base stations so eavesdropping on A5/1 is mostly used when lawful interception is not an option, e.g. listening to the GSM traffic of other countries.

  10. Re:If you don't like them hearing your private spe by Anonymous Coward · · Score: 4, Insightful

    > [1. It's interesting to note you can't translate "reasonableness" into Latin or modern French. It seems to be something very English-language-specific. My college's motto, "Let Reasonableness Flourish", is in English because of that oddity, and it says interesting things about other countrys' jurisprudence.]

    After five years of Latin, I feel fairly confident in saying the following:

    rationabilis is Latin for "reasonable" or "rational".

    -itas is the Latin suffix for "-ness".

    Thus, it would be fair to say that "rationabilitas" is Latin for "reasonableness". So no, reasonableness is not an English-language specific concept. And no, it doesn't imply shit about anything.

  11. VoIP + ZRTP by mrchaotica · · Score: 5, Informative

    I haven't tried it out yet, but ZRTP apparently provides strong (PGP-based) encryption for VoIP. So why not just quit using cellphone "voice calls" entirely? There exist cellphone plans that provide enough data cheaply enough to make this work economically.

    --

    "[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz

  12. Re:Only Logical by NormalVisual · · Score: 3, Interesting

    And the other part of the problem is that those charged with enforcing the laws won't do it. Both James Clapper and Keith Alexander have openly admitted to lying before Congress (which is a federal felony) regarding the NSA issue, and no one responsible for enforcing the law has said boo about it.

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