Encryption
Encryption is the process of converting plain text to cipher text using an algorithm. If files are encrypted, then if they are intercepted during transmission, they are
unreadable. When files reach their destination, they can be decrypted again.
The Ceaser cipher is an example of a simple encryption algorithm. Each letter in a message is moved
a certain number of characters on in the alphabet. If this increment takes you past the end of the alphabet you simply loop back to the start. So 'zap' with a shift of three letters
becomes 'cds'.
IP addresses
Devices connected to a network get an IP address. The switch or wireless router has a record of which node is at which address. An IPV4 address consists of 4 numbers between 0
and 255 e.g. 123.45.187.0. This means they are represented by 4 groups of 8 bits.
Although IPV4 allows for 232 or 4,294,967,296 addresses, the advent of the Internet of things has meant these were running out. IPV6 uses 8 sets of 4 hex digits. As
we know one hex digit represents 4 binary digits so this gives us 2128 or 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses. We shouldn't be running out of
those any time soon.
MAC addressing
A MAC address is made up of 6 groups of 2 hex digits e.g. 13:A6:ED:62:08:B3. It is a unique serial code hard coded into network interface cards when the device is manufactured
Even when a device logs on with a dynamic IP, it can be identified by the network because of its MAC address.