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Brin: Quantum Cryptography Outperformed By Thermodynamics

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  • KZK
    http://www.technologyreview.com/view/428202/quantum-cryptography-outperformed-by-classical/ The idea is straightforward. Alice wants to send Bob a message via
    Message 1 of 13 , Jun 14 9:31 PM
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      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
      Clever. I will talk the DoD into implementing it with Google Tap! ________________________________ From: KZK To: brin-l@mccmedia.com
      Message 2 of 13 , Jun 14 11:08 PM
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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 3 of 13 , Jun 14 11:21 PM
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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 4 of 13 , Jun 14 11:37 PM
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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 5 of 13 , Jun 15 5:03 AM
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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 6 of 13 , Jun 15 6:31 AM
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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 7 of 13 , Jun 15 10:35 AM
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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 8 of 13 , Jun 15 11:04 AM
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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 9 of 13 , Jun 15 11:14 AM
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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 10 of 13 , Jun 15 11:48 AM
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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 11 of 13 , Jun 15 12:28 PM
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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 12 of 13 , Jun 15 12:37 PM
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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 13 of 13 , Jun 15 6:20 PM
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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
                            Your message has been successfully submitted and would be delivered to recipients shortly.