You rotate the letters by a deterministic amount, by a fixed number of steps so that the end result is actually something that can be reversed.

你用确定的数量旋转那些字母，通过一个固定数量的步骤,这样，最终结果是可以把它,反加密出来。

哈佛公开课 - 计算机科学课程节选

As I said, what we want to do is, we want to count the number of basic steps it takes to compute a computation as a function of input size.

我刚才提到了，我们要建立，一个根据输入大小的方法来计算,一个计算过程需要的时间,建立这个方法需要几步呢？

麻省理工公开课 - 计算机科学及编程导论课程节选

I've got one test, I've got a subtraction, I've got a multiplication, that's three steps, plus whatever number of steps it takes to solve a problem of size b minus 1.

我进行了一次比较，一次减法，一次乘法，一共是三个步骤,再加上t的步骤数。

麻省理工公开课 - 计算机科学及编程导论课程节选