Re: Give me your password- OR ELSE!
From: "Philippe Nave" <pdn@dwroll.dw.att.com> Jim Miller writes :
Assume you use strong crypto to protect your secrets. Assume a lot of people start using crypto to protect their secrets. Assume there are people who want to discover these secrets.
Might we some day see an increase in the number physical attacks as bad guys resort to rubber-hose methods to get at the keys that protect the secrets?
I think this phenomenon is more or less inevitable, unless serious thought is given to a way to prevent it. Let's take a simple example and progress to a more complex scenario: (Interesting examples deleted)
One can think up all sorts of hypothetical scenes. Underneath it all however, I believe is a simple axiom. When prevention methods thwart a criminals intent, they find new methods. Car alarms and security systems didn't convince the criminals who make their living ripping off cars that the *Good ole days were over* and it was time to get a job at Burger Sri, it spurred them to find new methods to ply their trade. Beyond that it didn't bother them to up the ante regarding the level of violence they would utilise. Now extrapolate that into the concept of industrial espionage, white collar crime, and put everyone on the same wire. !!!!! LUX ./. owen
Car alarms and security systems didn't convince the criminals who make their living ripping off cars that the *Good ole days were over* and it was time to get a job at Burger Sri, it spurred them to find new methods to ply their trade.
How do you know this? Clearly some crooks may have just moved to more violent methods, but it's quite probable that others moved off to other fields where it's easier to make a buck, either legal or illegal. Although widely deployed strong cryptography may well cause an increase in violent, rubber-hose cryptanalysis, this technique is likely to be useful only for stored encrypted records and for encrypted communications whose protocols are not secure against this type of attack, e.g., PGP encrypted email. But much better protocols exist where online two-way communication is possible, e.g., signed Diffie-Hellman key exchange, with periodic automatic rekeying. Once you rekey in such a system, no amount of rubber hosing will obtain prior session keys; they're gone even to the participants. And even if you rubber-hose one of the participants into revealing the RSA key he uses to sign his DH exchanges, this will only let you masquerade as him in future conversations. In order to tap his future conversations surreptitiously, you'd have to rubberhose him without his knowledge, or hypnotize him into forgetting the incident. I'd say this is difficult. More so than secretly hacking the machine he uses to capture his secrets. Once again, it comes down to some level of physical security, at least while the machine is in actual use. Phil
participants (2)
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karn@qualcomm.com -
owen@autodesk.com