Re: Brin: Quantum Cryptography Outperformed By Thermodynamics
Clever. I will talk the DoD into implementing it with Google Tap! From: KZK evil.ke...@gmail.com To: brin-l@mccmedia.com 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 ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
Re: Brin: Quantum Cryptography Outperformed By Thermodynamics
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 ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
Re: Brin: Quantum Cryptography Outperformed By Thermodynamics
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. ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
Re: Brin: Quantum Cryptography Outperformed By Thermodynamics
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 ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
Re: Brin: Quantum Cryptography Outperformed By Thermodynamics
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. ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
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 ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
Re: Brin: Quantum Cryptography Outperformed By Thermodynamics
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 ___ http://box535.bluehost.com/mailman/listinfo/brin-l_mccmedia.com
