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Re: Brin: Quantum Cryptography Outperformed By Thermodynamics

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  • David Brin
    Clever. I will talk the DoD into implementing it with Google Tap! ________________________________ From: KZK To: brin-l@mccmedia.com
    Message 1 of 13 , Jun 14, 2012
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      Clever.  I will talk the DoD into implementing it with "Google Tap!"


      From: KZK <evil.kezik@...>
      To: brin-l@...
      Sent: Thu, June 14, 2012 8:31:47 PM
      Subject: Brin: Quantum Cryptography Outperformed By Thermodynamics

      http://www.technologyreview.com/view/428202/quantum-cryptography-outperformed-by-classical/

      The idea is straightforward. Alice wants to send Bob a message via an ordinary wire. At each end of the wire, there are two different resistors that correspond to a 0 or 1.

      Alice encodes her message by connecting these two resistors to the wire in the required sequence.

      Bob, on the other hand, connects his resistors to the wire at random.

      The crucial part of this set up is that the actual current and voltage through the wire is random, ideally Johnson noise. The essential features of this noise are determined by the combination of resistors at each end. This noise is public--anybody can see or measure it.

      Now here's the clever bit. Bob knows which resistor he connected to the wire and so can work out which resistor Alice must have connected.

      But  Eve, who is listening in to the publicly available noise, does not know which resistor was connected at each end and cannot work it out either because the laws of thermodynamics prevent the extraction of this information from this kind of signal.



      -----
      "It’s cheap to maintain Lies and expensive to maintain Trvth."
      --KZK's Maxim


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    • David Brin
      Oh by the way, many of you probably received my annual newsletter during the last couple of days. So you know about my book tour schedule, with in-person
      Message 2 of 13 , Jun 14, 2012
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        Oh by the way, many of you probably received my annual newsletter during the last couple of days. So you know about my book tour schedule, with in-person events in Seattle, Portland, the Bay Area, LA and San Diego area.

        Also see http://www.davidbrin.com for info about a Tweet extravaganza on 6/20 ( 1pm) #TorChat... and a Reddit "Ask Me Anything" marathon on 6/26!

        I assume you all have seen my new web site http://www.davidbrin.com

        ...and the fantastic preview trailer that Patrick Farley painted and executed for me! tinyurl.com/exist-trailer

        Sorry for the salesmanship, but I'm working hard!  And it has been 8 years since a "big brin book" so I hope you don't mind!

        Best to all.
        davidb
      • KZK
        ... So why isn t this susceptible to a simple man in the middle attack?: Eve cuts the wire between Alice and Bob (AB line) and insert her own node that
        Message 3 of 13 , Jun 14, 2012
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          > The idea is straightforward. Alice wants to send Bob a message via an
          > ordinary wire. At each end of the wire, there are two different
          > resistors that correspond to a 0 or 1. Alice encodes her message by
          > connecting these two resistors to the wire in the required sequence.
          > Bob, on the other hand, connects his resistors to the wire at
          > random. The crucial part of this set up is that the actual current
          > and voltage through the wire is random, ideally Johnson noise. The
          > essential features of this noise are determined by the combination of
          > resistors at each end. This noise is public--anybody can see or
          > measure it. Now here's the clever bit. Bob knows which resistor he
          > connected to the wire and so can work out which resistor Alice must
          > have connected. But Eve, who is listening in to the publicly
          > available noise, does not know which resistor was connected at each
          > end and cannot work it out either because the laws of thermodynamics
          > prevent the extraction of this information from this kind of signal.

          So why isn't this susceptible to a simple man in the middle attack?:

          Eve cuts the wire between Alice and Bob (AB line) and insert her own
          node that connects to Alice (AE line) and Bob (BE Line) individually.
          Alice can't tell the difference between the AB line or the AE Line and
          sets her resisters. Eve sets her resisters connected on the AE line to
          random and deciphers the sequence that Alice used. Eve then Uses that
          sequence on the BE Line. Bob can't tell the difference between the AB
          line and the BE line, sets his resisters randomly and decodes the
          message. (Eve can even send Bob a False message).

          Seems like this method requires a 100% secure land line, which is
          impractical.


          -----
          "It’s cheap to maintain Lies and expensive to maintain Trvth."
          --KZK's Maxim

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        • Ronn! Blankenship
          ... So while this is going on, what are Carol and Ted up to? _______________________________________________
          Message 4 of 13 , Jun 15, 2012
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            At 11:31 PM Thursday 6/14/2012, KZK wrote:
            >http://www.technologyreview.com/view/428202/quantum-cryptography-outperformed-by-classical/
            >
            >The idea is straightforward. Alice wants to send Bob a message via
            >an ordinary wire. At each end of the wire, there are two different
            >resistors that correspond to a 0 or 1.
            >
            >Alice encodes her message by connecting these two resistors to the
            >wire in the required sequence.
            >
            >Bob, on the other hand, connects his resistors to the wire at random.
            >
            >The crucial part of this set up is that the actual current and
            >voltage through the wire is random, ideally Johnson noise. The
            >essential features of this noise are determined by the combination
            >of resistors at each end. This noise is public--anybody can see or measure it.
            >
            >Now here's the clever bit. Bob knows which resistor he connected to
            >the wire and so can work out which resistor Alice must have connected.



            So while this is going on, what are Carol and Ted up to?





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          • David Hobby
            ... KZK-- I believe that Alice and Bob are doing the resistor thing for each bit simultaneously, and sharing their measurements over a separate open channel.
            Message 5 of 13 , Jun 15, 2012
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              On 6/15/2012 2:37 AM, KZK wrote:
              >> But Eve, who is listening in to the publicly
              >> available noise, does not know which resistor was connected at each
              >> end and cannot work it out either because the laws of thermodynamics
              >> prevent the extraction of this information from this kind of signal.
              >
              > So why isn't this susceptible to a simple man in the middle attack?:
              >
              > Eve cuts the wire between Alice and Bob (AB line) and insert her own
              > node that connects to Alice (AE line) and Bob (BE Line) individually.
              > Alice can't tell the difference between the AB line or the AE Line and
              > sets her resisters. Eve sets her resisters connected on the AE line
              > to random and deciphers the sequence that Alice used. Eve then Uses
              > that sequence on the BE Line. Bob can't tell the difference between
              > the AB line and the BE line, sets his resisters randomly and decodes
              > the message. (Eve can even send Bob a False message).
              >
              > Seems like this method requires a 100% secure land line, which is
              > impractical.

              KZK--

              I believe that Alice and Bob are doing the resistor thing for each bit
              simultaneously,
              and sharing their measurements over a separate open channel. (The paper
              says the
              voltage/current data on the noisy channel is "public".) Furthermore,
              they're tossing
              all the trials where those data show they both picked the "high"
              resistors or both
              picked the "low". So all Eve can usefully look at are data for
              essentially identical
              trials, each one with the noise characteristic of one high and one low
              resistor on the
              channel. Eve is free to relay noise between the two lines in your
              example, but that
              won't help her.

              If the land line is tapped in a useful manner, the claim is that Alice
              and Bob can
              detect that it is. So they'd need a land line, but wouldn't have to
              secure it.

              ---David


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            • David Hobby
              ... Between ALL communications channels, even the public ones? That s asking rather a lot of Eve. I think there are a lot of people who would use a
              Message 6 of 13 , Jun 15, 2012
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                On 6/15/2012 2:14 PM, KZK wrote:
                >>>
                >>> Eve cuts the wire between Alice and Bob (AB line) and insert her own
                >>> node that connects to Alice (AE line) and Bob (BE Line) individually.
                >>> Alice can't tell the difference between the AB line or the AE Line
                >>> and sets her resisters. Eve sets her resisters connected on the AE
                >>> line to random and deciphers the sequence that Alice used. Eve then
                >>> Uses that sequence on the BE Line. Bob can't tell the difference
                >>> between the AB line and the BE line, sets his resisters randomly and
                >>> decodes the message. (Eve can even send Bob a False message).
                >
                >> David Hobby Fri, 15 Jun 2012 06:31:29 -0700:
                >>
                >> I believe that Alice and Bob are doing the resistor thing for each
                >> bit simultaneously, and sharing their measurements over a separate
                >> open channel.
                >
                > And so Eve man-in-the-middles the second connection too. So all of
                > Alice and Bob's communications are with eve, so that (Eve and Alice)
                > And (Eve and Bob) are doing the resistor thing for each bit
                > simultaneously (but not Alice and Bob, they have no connection with
                > each other), and (Eve and Alice) And (Eve and Bob) are sharing their
                > measurements over the separate lines (but not Alice and Bob, they have
                > no connection with each other). Bob still can't tell the difference
                > between Eve and Alice and Alice can't tell the difference between Eve
                > and Bob.
                > ...
                > Doesn't matter, so long as Eve is between all communications channels.

                Between ALL communications channels, even the public ones? That's asking
                rather a lot of Eve. I think there are a lot of people who would use a
                cryptographic
                system that required an additional open channel, confident that they
                could somehow
                route around Eve most of the time. (Alice and Bob could be just posting
                their
                versions of the public information on their respective websites, and
                checking that
                they agreed.)

                But yes, it's a minor flaw that was not mentioned in the press release.

                ---David

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              • Dave Land
                ... I think you can be forgiven, particularly if there s any chance that your Bay Area friends can buy you a drink while you re here. If you have any time in
                Message 7 of 13 , Jun 15, 2012
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                  On Jun 14, 2012, at 11:21 PM, David Brin wrote:

                  Sorry for the salesmanship, but I'm working hard!  And it has been 8 years since a "big brin book" so I hope you don't mind!

                  I think you can be forgiven, particularly if there's any chance that your Bay Area friends can buy you a drink while you're here. If you have any time in the evening, I'd like to see you, and one or two others maybe, too?

                  Dave


                • KZK
                  ... And so Eve man-in-the-middles the second connection too. So all of Alice and Bob s communications are with eve, so that (Eve and Alice) And (Eve and Bob)
                  Message 8 of 13 , Jun 15, 2012
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                    >> On 6/15/2012 2:37 AM, KZK wrote:
                    >>
                    >> > But Eve, who is listening in to the publicly available noise, does
                    >> > not know which resistor was connected at each end and cannot work it
                    >> > out either because the laws of thermodynamics prevent the extraction
                    >> > of this information from this kind of signal.
                    >>
                    >>
                    >> So why isn't this susceptible to a simple man in the middle attack?:
                    >>
                    >>
                    >> Eve cuts the wire between Alice and Bob (AB line) and insert her own
                    >> node that connects to Alice (AE line) and Bob (BE Line) individually.
                    >> Alice can't tell the difference between the AB line or the AE Line
                    >> and sets her resisters. Eve sets her resisters connected on the AE
                    >> line to random and deciphers the sequence that Alice used. Eve then
                    >> Uses that sequence on the BE Line. Bob can't tell the difference
                    >> between the AB line and the BE line, sets his resisters randomly and
                    >> decodes the message. (Eve can even send Bob a False message).
                    >>
                    >>
                    >> Seems like this method requires a 100% secure land line, which is
                    >> impractical.
                    >
                    > David Hobby Fri, 15 Jun 2012 06:31:29 -0700:
                    >
                    > I believe that Alice and Bob are doing the resistor thing for each
                    > bit simultaneously, and sharing their measurements over a separate
                    > open channel.

                    And so Eve man-in-the-middles the second connection too. So all of
                    Alice and Bob's communications are with eve, so that (Eve and Alice) And
                    (Eve and Bob) are doing the resistor thing for each bit simultaneously
                    (but not Alice and Bob, they have no connection with each other), and
                    (Eve and Alice) And (Eve and Bob) are sharing their measurements over
                    the separate lines (but not Alice and Bob, they have no connection with
                    each other). Bob still can't tell the difference between Eve and Alice
                    and Alice can't tell the difference between Eve and Bob.

                    > (The paper says the voltage/current data on the noisy
                    > channel is "public".) Furthermore, they're tossing all the trials
                    > where those data show they both picked the "high" resistors or both
                    > picked the "low". So all Eve can usefully look at are data for
                    > essentially identical trials, each one with the noise characteristic
                    > of one high and one low resistor on the channel. Eve is free to relay
                    > noise between the two lines in your example, but that won't help
                    > her.

                    Doesn't matter, so long as Eve is between all communications channels.

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                  • Nick Arnett
                    Sure wish I could participate, but I m headed to the Big Boulder conference, in Boulder, Colorado, that weekend... disappointed! Nick ...
                    Message 9 of 13 , Jun 15, 2012
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                      Sure wish I could participate, but I'm headed to the Big Boulder conference, in Boulder, Colorado, that weekend... disappointed!

                      Nick

                      On Fri, Jun 15, 2012 at 11:04 AM, Dave Land <dmland@...> wrote:
                      On Jun 14, 2012, at 11:21 PM, David Brin wrote:

                      Sorry for the salesmanship, but I'm working hard!  And it has been 8 years since a "big brin book" so I hope you don't mind!

                      I think you can be forgiven, particularly if there's any chance that your Bay Area friends can buy you a drink while you're here. If you have any time in the evening, I'd like to see you, and one or two others maybe, too?

                      Dave



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                    • KZK
                      ... So Eve Man-in-the-middles Bob s connection to his webserver. Bob thinks he s writing information to correlate with Alice. What actually happens is Eve
                      Message 10 of 13 , Jun 15, 2012
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                        > David Hobby Fri, 15 Jun 2012 10:35:51 -0700:
                        >
                        > Between ALL communications channels, even the public ones? That's
                        > asking rather a lot of Eve. I think there are a lot of people who
                        > would use a cryptographic system that required an additional open
                        > channel, confident that they could somehow route around Eve most of
                        > the time. (Alice and Bob could be just posting their versions of the
                        > public information on their respective websites, and checking that
                        > they agreed.)

                        So Eve Man-in-the-middles Bob's connection to his webserver. Bob thinks
                        he's writing information to correlate with Alice. What actually happens
                        is Eve replaces the data Bob uses with the data from the Eve-Alice
                        connection. When Bob is connected to the website he see's the
                        information he thinks he's posted (Because Eve knows to change it back
                        for him, and only him, (also Alice's website data must be changed for
                        Bob and only Bob)). Etc.

                        Complicated? Yes, But plausible (this is sort of how the Sony Rootkit
                        worked).

                        > But yes, it's a minor flaw that was not mentioned in the press
                        > release.

                        Seems like it might be impractical. CITOKATE.

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                      • KZK
                        ... FYI: Pretty sure you need the colon in Brin: for messages to be sent to DB. _______________________________________________
                        Message 11 of 13 , Jun 15, 2012
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                          > Dave Land
                          > Fri, 15 Jun 2012 11:04:21 -0700
                          >
                          > I think you can be forgiven, particularly if there's any chance that your Bay
                          > Area friends can buy you a drink while you're here. If you have any time in the
                          > evening, I'd like to see you, and one or two others maybe, too?

                          FYI: Pretty sure you need the colon in "Brin:" for messages to be sent
                          to DB.


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                        • Medievalbk@aol.com
                          At every stop, there should be a What s next? question. In a message dated 6/14/2012 11:21:34 P.M. US Mountain Standard Time, dbrin@sbcglobal.net writes: Ask
                          Message 12 of 13 , Jun 15, 2012
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                            At every stop, there should be a "What's next?" question.
                             
                            In a message dated 6/14/2012 11:21:34 P.M. US Mountain Standard Time, dbrin@... writes:
                            Ask Me Anything" marathon
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