Re: [PATCH] arc4random.3: New page documenting the arc4random(3) family of functions

[Jakub Wilk <jwilk@jwilk.net>]

* Alejandro Colomar <alx.manpages@gmail.com>, 2023-01-01 17:27:
>arc4random_uniform() returns a random number less than upper_bound for 
>valid input, or 0 when upper_bound is invalid.

Is the "or 0 ..." thing part of the API? I could find anything like that 
in glibc docs or BSD man pages.

>STANDARDS
>       These nonstandard functions are present in several Unix systems.

That's not really helpful. Also, the VERSIONS section is missing ("every 
new interface should include a VERSIONS section").

In contrast, the libbsd man page is much more informative:

>These functions first appeared in OpenBSD 2.1, FreeBSD 3.0, NetBSD 
>1.6, and DragonFly 1.0.  The functions arc4random(), arc4random_buf() 
>and arc4random_uniform() appeared in glibc 2.36.
>
>The original version of this random number generator used the RC4 (also 
>known as ARC4) algorithm.  In OpenBSD 5.5 it was replaced with the 
>ChaCha20 cipher, and it may be replaced again in the future as 
>cryptographic techniques advance.  A good mnemonic is “A Replacement 
>Call for Random”.

-- 
Jakub Wilk