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