This doesn't have the potential blocking issue of the getentropy call
(which calls WASI random_get when using wasi-libc) and should therefore
be a lot faster.
For context, this is what the random_get documentation says:
> Write high-quality random data into a buffer. This function blocks
> when the implementation is unable to immediately provide sufficient
> high-quality random data. This function may execute slowly, so when
> large mounts of random data are required, it's advisable to use this
> function to seed a pseudo-random number generator, rather than to
> provide the random data directly.
This package provides access to an operating system resource
(cryptographic numbers) and so needs to be replaced with a TinyGo
version that does this in a different way.
I've made the following choices while adding this feature:
- I'm using the getentropy call whenever possible (most POSIX like
systems), because it is easier to use and more reliable. Linux is
the exception: it only added getentropy relatively recently.
- I've left bare-metal implementations to a future patch. This because
it's hard to reliably get cryptographically secure random numbers on
embedded devices: most devices do not have a hardware PRNG for this
purpose.
