The rand_bytes
function binds to RAND_bytes
in OpenSSL to generate cryptographically strong pseudo-random bytes. See
the OpenSSL documentation for what this means.
rnd <- rand_bytes(10)
print(rnd)
[1] f6 41 57 0d 60 29 67 05 5d 4c
Bytes are 8 bit and hence can have 2^8 = 256
possible
values.
as.numeric(rnd)
[1] 246 65 87 13 96 41 103 5 93 76
Each random byte can be decomposed into 8 random bits (booleans)
x <- rand_bytes(1)
as.logical(rawToBits(x))
[1] FALSE TRUE FALSE FALSE TRUE FALSE TRUE FALSE
rand_num
is a simple (2 lines) wrapper to
rand_bytes
to generate random numbers (doubles) between 0
and 1.
rand_num(10)
[1] 0.8745923 0.3240973 0.8996537 0.4861556 0.8782667 0.1466306 0.1331707
[8] 0.2758960 0.7849600 0.6264238
To map random draws from [0,1] into a probability density, we can use
a Cumulative
Distribution Function. For example we can combine qnorm
and rand_num
to simulate rnorm
:
# Secure rnorm
x <- qnorm(rand_num(1000), mean = 100, sd = 15)
hist(x)
Same for discrete distributions:
# Secure rbinom
y <- qbinom(rand_num(1000), size = 20, prob = 0.1)
hist(y, breaks = -.5:(max(y)+1))