Since encrypted data is indistinguishable from random noise, I think poor compressibility is actually zero compressibility, isn't it?
There are tools to search for TrueCrypt / other encrypted partitions on disks, so it's a solved problem to detect encrypted data.
It would be unfortunate if services ban the ability to upload encrypted secrets, though. On the other hand, that'd be good for Tarsnap. I wonder how much it'd cost to store 10TB on it?
The first billion of digits of Pi might look pretty random, but there might be a short program which genrates them - which can be considered a compressed form. In general, it is impossible to decide how good a given string might be compressed.
https://en.wikipedia.org/wiki/Kolmogorov_complexity
Since encrypted data is indistinguishable from random noise, I think poor compressibility is actually zero compressibility, isn't it?
I don't think so. Random noise can take any form - even of a string composed entirely of zeros, which would be trivially compressed. It's just very unlikely that it'll actually be compressible.
The definition of a random number is in the process of generation. You have to actually generate random numbers if you want to have a random number that meets some criteria. And even with impossibly vast resources, you will never find a random megabyte that compresses well.
Well, sure, that's what I wrote: "it's very unlikely that it'll actually be compressible." But it's incorrect to claim that random numbers are by definition non-compressible.
It was in the context of encryption. Even a 64 digit random number is very unlikely to be compressible, and 64 bytes is about as small of an encrypted partition as you'll ever have.
It'd take longer than the universe has left to find a string of N zeroes by generating random numbers, for sufficiently large N. And N is surprisingly small.
Yes zero. As zero as zero can possibly be, measuring with the most precise instruments possible. There's an infinitely better chance of both of us being struck by lightning and imagining you found such a number randomly.
It wouldn't be zero in certain math worlds. It is zero in the real universe.
How is Amazon supposed to distinguish between encrypted and non-encrypted data that you upload?