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] d7 98 fd 91 0d 4a ba 23 6d 95Bytes are 8 bit and hence can have 2^8 = 256 possible
values.
as.numeric(rnd) [1] 215 152 253 145  13  74 186  35 109 149Each random byte can be decomposed into 8 random bits (booleans)
x <- rand_bytes(1)
as.logical(rawToBits(x))[1] FALSE  TRUE FALSE FALSE  TRUE  TRUE  TRUE  TRUErand_num is a simple (2 lines) wrapper to
rand_bytes to generate random numbers (doubles) between 0
and 1.
rand_num(10) [1] 0.911241455 0.307891847 0.329681882 0.047568901 0.586398884 0.767603851
 [7] 0.085784320 0.002575604 0.538053861 0.503014223To 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))