/ dev/random权限被拒绝

Question

我正在阅读随机数和他们的一代.自从我开始编程以来,我对随机性很感兴趣.我读到Linux内核也使用随机数生成架构.

The structure consists of a two-level cascaded sequence of pools coupled with 
CSPRNGs.
Each pool is a large group of bits which represents the current state of the 
random number generator. The CSPRNGs are currently based on SHA-1, but the 
kernel developers are considering a switch to SHA-3.

The kernel RNG produces two user-space output streams. One of these goes to 
/dev/urandom and also to the kernel itself; the latter is useful because there 
are uses for random numbers within the kernel. The other output stream goes to
/dev/random. The difference between the two is that /dev/random tries to estimate
how much entropy is coming into the system, and will throttle its output if there 
is insufficient entropy. By contrast, the /dev/urandom stream does not throttle
output, and if users consume all of the available entropy, the interface degrades
to a pure CSPRNG.

所以,我兴奋地试着进入并查看/ dev/random和/ dev/urandom中的内容.但它说,

root@ubuntu:/home/sunny# /dev/random
bash: /dev/random: Permission denied

root@ubuntu:/home/sunny# /dev/urandom
bash: /dev/urandom: Permission denied

但是,当我用"ls"命令检查时,我可以在/ dev中看到"随机".我想详细了解这一点.

Answer 1

/dev/random不是可执行文件.试试cat /dev/random.或者,如果您不喜欢测试您的反应,dd if=/dev/random bs=128 count=1则会显示有限数量的随机垃圾.