cryptography

Question 1

Crytography

Answer 1

Studying, creating and solving coded messages.

Question 2

Encrypting

Answer 2

Creating coded messages.​

Question 3

Decrypting

Answer 3

Solving coded messages.​

Question 4

Caesar Cipher

Answer 4

The oldest coding method is called the Caesar Cipher, named after Julius Caesar.​

It works by shifting the alphabet by a set number of places, left or right, and uses this shifted alphabet to code the message.​

Caeser Cipher is very simple and can be easily cracked today.​

Question 5

Alan Turing

Answer 5

Alan Turing is a famous mathematician and cryptologist that worked at Bletchley Park to crack the German Enigma machine during World War 2.​

He designed and created a machine to decrypt the enigma machine and help win the war.​

Question 6

Barcodes

Answer 6

Barcodes are an example of encryption because they are a message with a hidden meaning that can only be understood using a laser to read them.​

Barcodes store, Product ID, Weight, Manufacturer, Country of Origin.​

They do not store the price of the product.​

The last number of a barcode is known as a Check Digit. This checks if the barcode is damaged.​

Question 7

Codes with MS Excel

Answer 7

Microsoft Excel can be used to convert letters into numbers and create coded messages.​

=code(cell) Turns the letter into a number.​

=chr(cell) Turn the number into a letter.​

We can add extra steps, such as adding and multiplying to scramble the message further.​

Question 8

PGP Encryption

Answer 8

PGP stands for ‘Pretty Good Privacy’. ​

It works by having a Public key which encrypts the message, and a Private key that decrypts the message.​

Anyone can see, and use, the Public key. The Public key uses a 256 bit number to shift each letter of the message by a different amount.​

Only the reader has the Private key, which is the only key that can unscramble the message.​

Having two different keys is known as ‘Asymmetric’ encryption.​