Re: Deniable Cryptography [was winnowing, chaffing etc]
-----BEGIN PGP SIGNED MESSAGE----- On 3/28/98 5:53 PM, mgraffam@mhv.net (mgraffam@mhv.net) passed this wisdom:
In this case, I figure that their best option is to beat Alice everyday forever or until she dies. Whichever comes first.
The longer they beat her, the better chance there is that she broke down and gave them her most important secrets. Even if she can't prove it.. so what? The rubber-hose group isn't exactly the boy scouts. They beat her the next day too, this time a little harder.
Alice may hold up, she may not.. I don't really see the cryptosystem helping here. You can't win a game when the other player doesn't use your rules. You have to use the same set of rules. We know that the rubber-hose wielding guys aren't going to play by Alice's rules. So, the only way for Alice to win is to do the impossible (because this is reality, not TV) and that is to grab the rubber hose and beat them with it.
The whole point is that since such a system offers no way to verify that Alice has indeed at any point given them 'everything' she has to tell, they will keep beating Alice; Alice, recognizing this at the outset has no reason to give them anything because she knows that since she cannot prove she has given them everything they will beat her again and again no matter what she does. The idea of successive keys unlocking more and more important data means that she can chose to give them some of her keys and then just grit out the beatings til they either develop conscience (unlikely), lose patience, (more likely), or figure they have gotten all there is to get. While this method guarantees a beating, it really does offer the best chance of getting away with the withholding of the most secure keys. The only chink in the system would be independent knowledge from a coworker or some such that there is more there. -----BEGIN PGP SIGNATURE----- Version: PGP for Personal Privacy 5.0 Charset: noconv iQEVAwUBNR2H/z7r4fUXwraZAQFbUgf/V97xgxpNs0wIcvUvoUK0p4gShYrzqDRm qXMz6rVTwMKNhBF/0Jdsfu8PMq7M6ZoU051I5FqYEgI2uaqUMxoPx9qjrGOJnOv3 pXr5usa4rRVv5k7mQOJjd1zXXbcJNo6QWWk35zbLS5ecXQgN98Ex2DgApxACzKin 6+rpaTPFzOaktIzSVvM0on2TcC7ifkhkzDjsqIYx3b3gp73p+kzlWgkxngSM2rXZ Od2eEQDSJDnQc4n5DU7xxmwQ5qxz5GCcQiONHkL4pXSHvkbvGkNkPS8Ms/hsF2nJ SiSlmoYQBem3YB/Ik1UEFrqOhRispsYU9NAgii7EtqyAReEnYMI1gQ== =0JND -----END PGP SIGNATURE----- Brian B. Riley --> http://members.macconnect.com/~brianbr For PGP Keys mailto:brianbr@together.net?subject=Get%20PGP%20Key "Do not go where the path may lead, go instead where there is no path, and leave a trail" - Ralph Waldo Emerson
-----BEGIN PGP SIGNED MESSAGE----- On Sat, 28 Mar 1998, Brian B. Riley wrote:
The whole point is that since such a system offers no way to verify that Alice has indeed at any point given them 'everything' she has to tell, they will keep beating Alice; Alice, recognizing this at the outset has no reason to give them anything because she knows that since she cannot prove she has given them everything they will beat her again and again no matter what she does.
She has a reason to tell them as much as she can. When she tells them a key that yields meaningful data, they stop beating her for the day. At some point she will give away all the keys that yield innocuous or less important data. Then she will say "I dont have anything else." Which the bad guys figure she is going to say at some point anyhow, and they keep beating her no matter what, as we agree they will probably do. At some point, she will give up that most important key just to escape the day's beating, or to get the knife removed from her hand.. If the attackers are smart, they would leave her alone for varying amounts of time, so that at any point the key that she gives might buy her a month or more of pain-free existence. Maybe more. If I were a bad guy, I'd opt for letting her live well for a few years, and then one day we start the beatings again, as often as possible (short of killing her). At some point, she'll say "The only key that I have left is the most important one. If I give it up, maybe I'll get another 2 years of the good life." She would know that I would never let her go, and she would know that the beatings would continue for the rest of her life. It simply becomes a matter of how much pain-free time she gives herself. If the attacker beat her every second of every day, no matter if she gives a key or not, then you are right. I suspect everyone would keep their mouth shut out of spite, if nothing else. But if the key she gives yields meaningful data, then the tables change really quickly. There is another point to realize, there is a point where you simply stop acting reasonably because of the pain and suffering.. and once reason is out the window, expecting Alice to hold on to the keys because she is screwed either way is a gamble. Sure, the scheme works when we are being reasonable, but when you get the side of your head smashed it, reasonableness is one of the first things to leave you. This is why I think that pursuing a biological form of authentication could be so useful. It could potentially make beating the person prolong the time needed to get the information. If the bioauthentication system could take biofeedback from feelings like intimidation or anxiety, and use these to alter the resulting "key" output, then it would actually behoove the attackers to give Alice a nice comfy bed and 3 squares a day. "Sometimes," she said, "they threaten you with something -- something that you can't stand up to, can't even think about." ... "Under the spreading chestnut tree I sold you and you sold me -" - Julia, and a portion of a song from "1984" Michael J. Graffam (mgraffam@mhv.net) http://www.mhv.net/~mgraffam -- Philosophy, Religion, Computers, Crypto, etc Let your life be a counter-friction to stop the machine. Henry David Thoreau "Civil Disobedience" -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 5.0i for non-commercial use Charset: noconv iQCVAwUBNR2gXAKEiLNUxnAfAQEpLwP9HUO8wGOGp6u7iSLcvzbB71m2BGgK1z7r 5ODfaIO4dLMwvUG8MPV6JedYDODVL+l6Ea7U8pKR/oO6fTV9Y2UhW8jSJunbgQ83 mIEAaZPCVpJxUELVBfpuQAkGIITOGiGjrmozlojH+l8x/AW0t3xyFQG/wvRwxBSO Z+EHWifLb38= =pbuj -----END PGP SIGNATURE-----
participants (2)
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Brian B. Riley
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mgraffam@mhv.net