> It takes a prohibitively long time to knock on 2^256 bricks
This assumes you have to knock on 2^256 bricks and not just wiggle the mortar free in one spot. WEP wifi encryption is an example of an implementation failure vs. theoretical time to brute force the encryption.
You're right, but the answer to encryption backdoors can't be "we don't think you'll make good enough backdoors". Even if the backdoor can't be opened by anything other than acquiring the government key, it's still not acceptable.
Yup, in fact that's my point. No matter how good the encryption or implementation is, there will always be a weak link and someone that finds a way in. For some people, its a fun challenge and bragging rights. For others, it's profit.
This assumes you have to knock on 2^256 bricks and not just wiggle the mortar free in one spot. WEP wifi encryption is an example of an implementation failure vs. theoretical time to brute force the encryption.