# Mathematical Foundations for Cryptography: Part II

In part I of this series, we introduced the idea of a cipher for encrypting and decrypting text between two entities. We now continue with part II, where we will learn how two different parties can establish a shared secret.

**PART II: A SHARED SECRET**

**Mathematical tools: The modulus and the power**

The first mathematical tool we are going to use is called the modulus function. To understand the modulus function, let’s look at an example. We want to know the value for **29 modulus 8**, or **29 mod 8** for…