[Cryptography] RNG design principles
leichter at lrw.com
Mon Nov 28 16:46:58 EST 2016
> ...Imagine the Linux kernel would provide a new, special
> file structure that has a property "read-once-and-then-never-again"
> enforced by kernel code. This file could be read (once) in early boot
> process and would not be accessible after that first read.
Hmm. Sounds kind of like a pipe, or a socket. The semantics is mainly already there, just not specifically as a file system.
> To update the secret stored in such a special file structure, there
> must be a second property "write-once-after-being-read-once" enforced
> by kernel code to make sure that the secret can only be changed by
> early boot code once enough entropy has been gathered to safely
> update the file content (once).
This could be done through something pipe- or socket-like, too - whatever is listening will only accept one write, then close its side.
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