Mitigating timing attacks with a random sleep Could you mitigate all timing attacks by putting a sleep(random()) with a naive crypto implementation? Eg if your implementation looks solid, but you're not sure what the next CPU cache vulnerability is around the corner, would this be a legitimate mitigation strategy?

To clarify, this would be a random delay measured from before the algorithm starts, so that you're not simply adding fuzz to the runtime.
Adding random sleep may make it slightly harder, but not more than that. The problem with adding random noise is that the average time will still be different between the two measurements you are trying to make. So, you will need more measurements, but eventually will get the right thing, since the averages will stand out. This is how timing attacks can be done over the Internet (see Remote Timing Attacks are Practical), even though there is timing noise in networks.