The question that many people keep asking is (__How does the RSA cipher work?__). In fact,

**RSA**

**cipher**consists of three basic steps, where you need to have at least some basic

**mathematical concepts**knowledge.

**The modulo operator.****Euler’s totient function.****Euler-Fermat theorem.**

First, you need to keep in mind the following concepts, since you will be using them continuously in Cryptography, especially RSA operation.

Simply any number/whole number and is not a fraction. For example, (0, 1, 2, 3, 4, 5 and more). Sometimes they are called natural numbers.__Integer numbers:__is a way of expressing a number that is a ratio of two integers. Usually fraction numbers are part of a whole or something. For example, 1/2, 1/8 and more.__Fraction number:__any number that is divisible only by itself and 1. For example, (2, 3, 5, 7, 11 and more).__Prime numbers:__are the numbers we multiply to get another number. For example, the factors of 15 are 3 and 5. In addition, some numbers have more than one factorisation or more than one way to do the factoring. For example, the factors of 12 could be (1×12), (2×6) or (3×4).__Factor numbers:__**Remember:**any number that can only be factored as 1 times itself is called “**Prime**”.in this__Modulo operation:__**modulo operation**, we are interested in the**remainder**() left over from the division with an integer number. For example,*r***16****≡****1 mod 5**. As a real-life example, 5 university students have ordered a large pizza. The pizza has arrived with 16 slides, where every student will eat 3 slides; and eventually 1 extra slide will remain (this slide is what we are after the reminder). Note: the modulo operation sign is “**≡**”. See the figures below for more details:

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