Can anyone advise on the theoretical basis for the unpredictableSeed method in std.random? I've tried googling around for the theory of good thread-safe seed generation methods but haven't really found anything. :-(
I have to ask: what would be a good unpredictableSeed by definition? With the current implementation, three downsides come to my mind:
1. Process ID, thread ID and system tick are insecure sources of randomness and can provide just a few bits of randomness in certain situations. I don't know how to address this in a portable way.
2. Once we know the first seed, it is easy to predict all subsequent seeds. A solution would be to use a secure RNG instead, not just the one which gives away its state.
3. It would be a particularly bad idea to initialize MinstdRand0 instances with consecutive unpredictableSeeds and then consider them independent. This is just a consequence of a particular choice of RNG on the previous step.
So, which of these do you consider the real problems, and what more do you need from unpredictableSeed?
----- Ivan Kazmenko.
