Cryptokit.Random unsuitable in cooperative multithreaded systems

[David Sheets <sheets@xxxxxxxxxxxx>]

Cryptokit.Random.secure_rng might use /dev/random for entropy
generation which might block if there isn't enough available entropy.
My local machine never seems to have low entropy with

$ cat /proc/sys/kernel/random/
entropy_avail
3480

but ocaml-www2 says

$ cat /proc/sys/kernel/random/entropy_avail
147

There are only a handful of Unix calls in the library...

Additionally, Vincent Bernardoff appears to have forked Cryptokit with
the unmerged addition of SHA-512 <https://github.com/vbmithr/cryptokit-sha512>.

What's the status of this library? Is it part of Mirage? Are we
forking it? Is it maintained?

I'm using Random for now as it doesn't really matter to have secure
RNG for ocamlot.

Thanks,

David