The private key will have a connection to one of the primes, and

with that number, I can decipher the message.

But it's computationally too hard for

someone else to work it out, and it may take forever.

I mean, the forever of everyone's life on this planet.

A process like this happens every time we have a secured transaction

online such as with online banking, and the padlock symbol appears.

Encryption is different from from steganography.

In steganography people see an image or a text, but it's normal and

there's no reason to suspect there is a secret message in it.

In encryption, a message may look unreadable,

such as, Sherlock Holmes was famous for using both.

Usually some sort of anagram of an encoded message that read like a real word.

But let's leave Sherlock in books, shall we?

The information is converted into a code.

The most secure system in classic computing relies on properties

of prime numbers.

Specifically on how hard it is to find prime numbers

that divide into a given number, if this number is very large.

This means that finding the correct key to unscramble

the encryption system in a timely fashion is extremely unlikely.

Doing it in a systematic manner is impossible using classic computers.

We will use your knowledge of working with integers, in particular prime numbers,

these will be key for modular arithmetic, encryption as well as decimals and

fractions.

Every technique you learn can be systematized, and

you will be invited to write informal algorithms for all of them.

If you want to take it further, always bear in mind implementing such algorithms

in a programming language you are learning or use it as an opportunity to learn one.

Programming is outside the scope of this module, but

the purpose of this topic is to prepare you for

when you use number bases, and modular arithmetic in computing.

In these first two weeks, topic one, you will aim to build

the mathematical skills to tackle the following problems,

steganography, using images, encryption, using prime numbers.

You will implement a simple instance of these problems using

the tools in our platform.

Don't worry if you are absolutely brand new to computing,

we have designed tools to support you.