Secure random number generation for mruby using system RNG facilities e.g. /dev/urandom, getrandom(2)

Description

In cryptography circles, the prevailing advice is to use OS RNG functionality, namely /dev/urandom or equivalent calls which use an OS-level CSPRNG to produce random numbers.

This gem provides an easy-to-install repackaging of the randombytes functionality from libsodium for the purpose of generating secure random numbers trustworthy for use in cryptographic contexts, such as generating cryptographic keys, initialization vectors, or nonces.

The following random number generators are utilized:

Usage

Sysrandom.random_bytes # returns a 16 byte binary string
Sysrandom.random_bytes(64)
Sysrandom.random_bytes(" " * 10)
Sysrandom.random # returns a number
Sysrandom.uniform(upper_bound) # returns a number up to upper_bound
Sysrandom.base64 # returns a 16 byte binary string as base64
Sysrandom.base64(64)
Sysrandom.base64(" " * 10)
Sysrandom.hex # returns a 16 byte binary string as hex
Sysrandom.hex(64)
Sysrandom.hex(" " * 10)