(1) Directory
l
prime number
l
Greatest common divisor and least common multiple
l
same surplus
l
first degree congruence equation
l
Euler's Theorem and Fermat's Little Theorem
l
Several applications of elementary number theory in computer science and technology
(2) Main content
l evenly divisible
l prime number
![](https://img-blog.csdnimg.cn/95c15cc2218343a5beae298bcdf79ba7.png)
![](https://img-blog.csdnimg.cn/92e823982b774929ae6b1357a2ccf163.png)
typical example:
l Fundamental Theorem of Arithmetic
l Greatest common divisor and least common multiple
nature
Roll and divide![](https://img-blog.csdnimg.cn/ebba67249c064b4f9d1c87dddc7c05b7.png)
l same surplus
Congruence
l first degree congruence equation
![](https://img-blog.csdnimg.cn/8cd3d053d5ca4ab88e40d778255ea8ae.png)
Modular inverse ![](https://img-blog.csdnimg.cn/59d56367b504441f82d18903946b926a.png)
Typical example:
l Euler's Theorem and Fermat's Little Theorem
l Several applications of elementary number theory in computer science and technology
Method to Generate Uniform Pseudorandom Numbers
Linear congruence and multiplication congruence![](https://img-blog.csdnimg.cn/b85405114e234837a459662f82100ae5.png)
Cryptography:
![](https://img-blog.csdnimg.cn/e148ff62b4a74da0abba1880ce659222.png)
Encryption Algorithm: