Introduction to Cybersecurity

Introduction to Cybersecurity. By Donald F. Costello Associate Professor Emeritus La Salle and PIUS HIGH SCHOOL.

Codes. Our Lives are filled with Codes Much of Modern Technology make use of Codes The various Codes we use today evolved as Technology Changed Let’s look at some clever uses of Codes over the years. Don’t get discouraged if you don’t catch some of this the first time. Most of us who studied codes didn’t catch on right away..

A picture containing text, newspaper Description automatically generated.

A picture containing text, indoor Description automatically generated.

Image courtesy of en.wikipedia.org.

Runes. Image courtesy of en.wikipedia.org.

A picture containing outdoor, grass, person, black Description automatically generated.

Abstract background. The DNA Code. DNA consists of a code language comprising four letters which make up what are known as codons, or words, each three letters long. These four coding units are in the form of the nucleobases: adenine (A), thymine (T), guanine (G) and cytosine (C)..

Was Julius Caesar Evil ?. A drawing of a person Description automatically generated with medium confidence.

Was Julius Caesar Noble?. A statue of a person Description automatically generated with medium confidence.

Et Tu Brute. A picture containing person, indoor, standing Description automatically generated.

Caesar needed to talk to his spies. Sometimes Caesar had to send messages to his spies. Here is how he did this. Caesar sent spies out to watch what the enemy was doing. The Spies were soldiers who were sent into the enemy region and communicated back to Caesar in a code invented by Caesar. Let me tell you about that code. Start taking notes!.

We are going to do a Caesar Code of 3. The Message we want to send in GOD. When we use a Caesar Code of 3 we shift each letter forward on the alphabet chain three letters..

Encoding “GOD”. Caesar -3. In a Cesar – 3 coding process one takes every letter in a string and moves to up three letters in the alphabet we use going from A to Z. If you were using an alphabet from another language, you would essentially do the same thing..

The Decoding Process. The receiver of the encoded Message must now what Encoding Scheme was used. Was it Caesar-3 or Caesar -10 or ??? Since it would be foolish to use the same Encoding Scheme every day, there must be an agreed upon protocol of what Encoding Scheme to use on each day..

More History of Caesar Code. It is unknown how effective the Caesar cipher was at the time, but it is likely to have been reasonably secure, not least because most of Caesar's enemies would have been illiterate and others would have assumed that the messages were written in an unknown foreign language. There is no record at that time of any techniques for the solution of simple substitution ciphers. The earliest surviving records date to the 9th century works of Al-Kindi in the Arab world with the discovery of frequency analysis..

A WW II Imitator of Caesar. In occupied France during WW II, a priest tapped out a message to members of the resistance group. When they received the message , they knew that the Germans had left the area. This let them storm the prison and storm the prison. This story is part of the movie entitled “ Circle of Deception” Note you don’t need a readable message. You previous agree on a sequence that signals the OK..

In Class Lab I. We’ll set you up in two person teams. You are going to be given a message to encode and then Person I is going to encode the message and send it to Person II. Person II is going to have to decode the message. We will assume that Person I will use a Caesar code larger than Caesar-3. Person II will know the version of Caesar being used. What makes this a challenge is that I will send the message to person I who will NOT share it with Person II..

Now take a code of Caesar 4 and code the Message ATTACK And send it to your partner His job is to decode The message.