On Mon, 30 Mar 1998, Jeremiah Blatz wrote:
"Rubber hose" cryptanalysis needn't involve actual beatings in secret underground cells. Simple example: Cops raid your house, rough you up a little bit (not much) and toss your ass in a cell with "real ' criminals. 12 hours later they take you into a room and play good cop/bad cop with you. Maybe you're not sure you could stand up to this, and might panic and reveal more than you have to (remember, you haven't been charged with a crime yet). However, if you do hold out, the chances that you'll be let go, and get your stuff back in a few years, are pretty high. In this case, being able to spill a key that revelas harmless stuff is good, since the police are unlekely to hold you for a long time.
Absolutably. I understand that deniabled crypto will help against a civilized enemy, but it is not an answer for the worst case scenario. I maintain that algorithms aren't what we really need for this type of key management. It is nice to be able to give up less important keys as a matter of convienence, but as long as the user can get the data so can an attacker. If we have a physical system that gets key information from the user through biological feedback that takes stress conditions, blood pressure, etc into account then if any of these signs are out of the norm the device can generate bad key information as a result of this. This insures that the user will not be able to get the information if he is being physically manipulated. This also has use in areas where we dont want the user to be authenticated when he is in an odd state of mind, such as when dealing with weapons systems. I dont think that biofeedback technology is at the point to make this usable yet, but I hope that advances are made quickly. The firearms maker Colt has explored authentication devices for their weapons, but I dont know the details. Michael J. Graffam (mgraffam@mhv.net) http://www.mhv.net/~mgraffam -- Philosophy, Religion, Computers, Crypto, etc "..subordination of one sex to the other is wrong in itself, and now one of the chief hindrances to human improvement.." John Stuart Mill "The Subjection of Women"