Comment Re:Self-Destructing Key (Score 1) 887
What you describe is not possible in any way.
An "encrytped hard drive" or an "encrypted file" are both the same thing: a very very large number. When the government took possession of the medium that stores that number, they then permanently know it. It's a series of 1s and 0s, and they have it for sure, definitely, it can never be altered. So whatever procedure you have in mind is like saying, what if the number 8 simply decays in September. It doesn't make any sense.
Well, yeah, the data will still be in tact for them to begin brute force cracking, but there are still plenty of ways to make "simple" decryption (even by the encrypter) difficult. I think someone above mentioned a USB drive or key that would self-destruct after so much time could be used, or something that without it, you can't decrypt the data easily. Thus, just knowing the password (or having the person type it) won't work.