mirror of
https://github.com/ilyakooo0/urbit.git
synced 2024-12-20 13:22:07 +03:00
25 lines
1.1 KiB
Markdown
25 lines
1.1 KiB
Markdown
libent is a cross-platform wrapper around `getentropy(2)`. It exports
|
|
one symbol, `ent_getentropy`, which expands to `getentropy` if the
|
|
latter is available. Otherwise, it tries to use the next best source of
|
|
entropy — `/dev/urandom` on *nix.
|
|
|
|
### Why?
|
|
|
|
`getentropy` is the wave of the future. It's the correct API for
|
|
generating small amounts of entropy to create cryptographic keys or seed
|
|
PRNGs. It's good and reasonable and true, it's on Linux, *BSD, and OS X,
|
|
and it only took us fifty years of UNIX to get here.
|
|
|
|
Sadly, it only just arrived, so nobody has it yet. It didn't land in
|
|
Linux until glibc 2.25, which seems to only have made it into Debian 10.
|
|
|
|
Once `getentropy` is everywhere you care about, you can just do a
|
|
s/ent_//g on all the call sites and discard this shim.
|
|
|
|
Admittedly, 90% of the motivation behind this was to fix the randomness
|
|
shim in [Urbit](https://github.com/urbit/urbit).
|
|
|
|
References:
|
|
* [OpenBSD getentropy](https://man.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man2/getentropy.2)
|
|
* [djb on entropy gathering](https://blog.cr.yp.to/20140205-entropy.html)
|