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Worksheets

Encryption & Decryption Tools

Total questions: 25

Worksheet time: 27mins

Name
Class
Date
1.

What is steganography?

a)

software that draws graphs

b)

a dinosaur

c)

hiding a secret message in a not secret computer file or message

d)

hiding a secret message in a physical object

2.

90% of the time when a computer gets hacked its because of 

a)

software design

b)

security bug

c)

human mistake

3.

Asymmetric encryption uses . . .

a)

2 public keys for encryption & decryption of messages

b)

1 private to encrypt messages and 1 public key to decrypt messages

c)

2 private keys for encryption & decryption of messages

d)

1 public key to encrypt messages and 1 private key to decrypt messages

4.

The plugboard on the Enigma Machine connects. . .

a)

the rotors to the letters

b)

pairs of letters that will be transposed

c)

unused pairs of letters

5.

If the sender and receiver agree on the key, it is known as

a)

128 Bit Key

b)

Asymmetric

c)

256 Bit Key

d)

Symmetric

6.

What is the algorithm of Ceasar's cipher?

a)

Each letter is replaced with a particular symbol

b)

Each letter is replaced with a letter a certain number of steps down the alphabet

c)

Each letter is replaced with a particular number from 0 to 26, and numbers are replaced with letters.

d)

Each letter is replaced with a completely random number

7.

The process of converting plaintext to ciphertext.

a)

cryptography

b)

cyphertext

c)

decryption

d)

encryption

8.

What encryption algorithm uses the same key to both encrypt and decrypt messages.

a)

Symmetric

b)

Asymmetric

9.

Who was the first known user of the Caesar Cipher?

a)

Tiberius Caesar

b)

Julius Caesar

c)

Augustus Caesar

d)

Claudius Caesar

10.

The Enigma machine uses symmetric encryption.

a)

True

b)

False

11.

An encryption algorithm transforms plain text into:

a)

Cipher text

b)

Simple Text

c)

Plain text

d)

Filled text

12.

In Cryptography, original message, before being transformed, is called

a)

Simple Text

b)

Plain Text

c)

Cipher Text

d)

Filled Text

13.

_______ is the science and art of transforming messages to make them secure and immune to attacks.

a)

Cryptoanalysis

b)

Cryptography

c)

neither Cryptography nor Cryptoanalysis

d)

either Cryptography or Cryptoanalysis

14.

The process of converting a ciphertext into plaintext.

a)

encryption

b)

decryption

c)

plaintext

d)

cryptography

15.

Consider the process of encoding and decoding a message using the following Caesar cipher encoding scheme in which the plaintext and ciphertext alphabets are offset by four positions, as shown below:

Plaintext: a b c d e f g h i j k l m n o p q r s t u v w x y z

Ciphertext: w x y z a b c d e f g h i j k l m n o p q r s t u v


Which of the following encoded ciphertext strings decodes to an original plaintext message of "secret"?

a)

etsecr

b)

wigvix

c)

kwujwl

d)

oaynap

16.

A Caesar cipher is an example of a ______________________.

a)

transposition cipher

b)

bimodal cipher

c)

substitution cipher

d)

substantial cipher

17.

Caeser achieved his cipher by shifting all the letters _____ spaces to the right.

a)

3

b)

1

c)

7

d)

13

18.

What term is used to describe concealing data in another file such as a graphic, audio, or other text file?

a)

masking

b)

obfuscation

c)

hiding

d)

steganography

19.

Codes have been used for thousands of years to:

a)

figure out where the enemy is

b)

send messages

c)

communicate with some people but not

d)

send secret messages back and forth

20.

Which of these is used regularly for secure online communication?

a)

Caesar cipher

b)

Morse code

c)

Public key cryptography

d)

Enigma code

21.

How can you tell if a website encrypts its traffic?

a)

Google it

b)

Look for the lock symbol in the URL

c)

All websites encrypt their traffic

d)

Encrypted sites take longer to load

22.

Consider the process of encoding and decoding a message using the following Caesar cipher encoding scheme in which the plaintext and ciphertext alphabets are offset by four positions, as shown below:

Ciphertext: w x y z a b c d e f g h i j k l m n o p q r s t u v

Plaintext: a b c d e f g h i j k l m n o p q r s t u v w x y z

Which of the following encoded ciphertext strings decodes to an original plaintext message of "secretd

Decode the following: yuxan

a)

crypt

b)

color

c)

cyber

d)

cystic

23.

Steganography is used only with text.

a)

True

b)

False

24.
What type of key is not shared and computers cannot decrypt a message without it?
a)
Free key
b)
Private key
c)
Public key
d)
Personal key
25.

Scrambling or changing a message to hide it is called

a)

Secure Communication

b)

Symmetric Encryption

c)

Encryption

d)

Public Keys