Mathematics set 2

Question 1

What is encryption?

Answer 1

Encryption is making data safe and secret

Question 2

What is decryption?

Answer 2

Decryption is the way to read the secret message.

Question 3

When is encryption and decryption vitally important?

Answer 3

During wartime.

Question 4

What was Bletchly Park?

Answer 4

Bletchly park was the center of encryption and decryption in England in World War 2

Question 5

What is a cryptologist?

Answer 5

A cryptologist is a person who works to decrypt secret messages from the enemy or encrypts messages into code

Question 6

What is the Enigma machine?

Answer 6

The Enigma machine was a cryptography machine created during WW2 by the Germans.

Question 7

How did the Enigma machine work?

Answer 7

The Enigma machine used keyboard and a set of rotating disks and electric circuits created codes.

Question 8

How did breaking the Enigma code help the war?

Answer 8

The British cryptographers broke the code and were able to find out the secret German messages, which helped them to win.

Question 9

What is a substitution code?

Answer 9

A substitution code replaces a letter with another letter or symbol

Question 10

How can a person decode a message written in a substitution code?

Answer 10

The person must need to know the replacement letters.

Question 11

What is an encryption key?

Answer 11

An encryption key is the code of replacements for a particular code

Question 12

What is a Caesar Shift Cipher?

Answer 12

A Caesar Shift Cipher replaces each letter with a letter a set distance away, and was used by Julius Caesar in Roman times.

Question 13

How can a person try to break a code?

Answer 13

Look at the frequent symbols as the letter ‘e’ is most frequently used.

Question 14

How can you make a code difficult to break?

Answer 14

Change as many letters as you can, so that it’s hard to find patterns.

Question 15

what is the problem with a Frequency Analysis?

Answer 15

Looking for the most frequent symbols or letters can only work to break the code if the message is very long.

Question 16

What is a symmetric key?

Answer 16

A Symmetric Key is used to make the message and to decode the message

Question 17

What is a draw back of a Symmetric Key?

Answer 17

It is very simple

Question 18

What is an uncoded message called?

Answer 18

An uncoded message is called plaintext

Question 19

What is a public-key encryption?

Answer 19

Public-key encryption has two different keys, a public key to encrypt and a private key to decrypt

Question 20

Why is public-key encryption safer?

Answer 20

Only the intended recipient getting the message knows the key to decrypt your message.

Question 21

What is a compression code?

Answer 21

A compression code re-writes information using fewer characters, so it takes less space on a computer and can be transmitted more quickly

Question 22

Wlcm to Chmns is what message?

Answer 22

Welcome to Chemainus with the vowels taken out.

Question 23

What is a JPEG?

Answer 23

A JPEG is a digital photo image.

Question 24

What does JPEG stand for?

Answer 24

Joint Photographic Experts Group, which is the name of the group that figured out how to compress images

Question 25

What is Morse Code?

Answer 25

Morse code is a message system that uses electricity.

Question 26

Who invented Morse Code?

Answer 26

Samuel Morse in 1844 invented Morse Code

Question 27

What is the machine that sends Morse Code?

Answer 27

An electric telegraph machine sends Morse Code

Question 28

How was Morse Code transmitted?

Answer 28

Morse code was transmitted over telegraph wires that carried electricity.

Question 29

How does Morse Code work?

Answer 29

Each letter is replaced by a system of dots and dashes

Question 30

Why is Morse Code a kind of compression code?

Answer 30

It is a compression code because the most used letters have the shortest sequences.

Question 31

What is Run-length coding?

Answer 31

Run-length coding is used on a fax machine (facsimile machine)

Question 32

How does a fax machine work?

Answer 32

A fax machine translates the image into sets squares in a fine grid, then sends the information as to whether the grid is full or not.

Question 33

What is the Arecibo Message?

Answer 33

The Arecibo Message was a message sent into space using a radio telescope

Question 34

How is regular coding different than run-length coding?

Answer 34

In regular coding you put a 0 if there is nothing in that spot, but a 1 if there is something in that spot, so it becomes a list of 0001110001110001010 etc. In run-length coding, you only put the number of the space that is full so 456 etc, so it takes less transmission space.