SecureRandom.gen_random_urandom

# File tmp/rubies/ruby-3.2.0/lib/securerandom.rb, line 63
def gen_random_urandom(n)
  ret = Random.urandom(n)
  unless ret
    raise NotImplementedError, "No random device"
  end
  unless ret.length == n
    raise NotImplementedError, "Unexpected partial read from random device: only #{ret.length} for #{n} bytes"
  end
  ret
end