Encryption

Encryption is a method of encoding data in a way that only authorised users can access it.

The basic idea is that we take our original data, called plaintext, and we use a maths function, called an encryption algorithm, to transform that plaintext into a new form, called ciphertext, which is unreadable to anyone who doesn’t have the key to decrypt it.
Sometimes we call this encryption algorithm the cipher.

Importantly, only the intended recipient of the data should have the key to decrypt it.

Why use encryption?

When we send data over the internet, anybody along the route of the ‘packet’ of data can read its contents.

It’s often important that we send data privately - things like passwords, card details, messages, etc. - so that only the intended person is able to read it!