在实际应用中往往使用伪随机数就足够了。这些数列是“似乎”随机的数，实际上它们是通过一个固定的、可以重复的计算方法产生的。计算机或计算器产生的随机数有很长的周期性。它们不真正地随机，因为它们实际上是可以计算出来的，但是它们具有类似于随机数的统计特征。这样的发生器叫做伪随机数发生器。

在真正关键性的应用中，比如在密码学中，人们一般使用真正的随机数。-In actual applications tend to use a pseudorandom number is sufficient. The number of columns is " as if"　a random number, in fact they are through a fixed, repeatable calculation produced. A random number generated by a computer or a calculator has a long periodicity. They are not really random, because they can actually be calculated, but they have similar statistical characteristics of random numbers. Such a pseudo random number generator is called the generator. In the real critical applications, such as in cryptography, people generally use a truly random number.