Terminology
Basics
Modular Arithmetic
Caesar and Pigpen Ciphers
Shift and Vigenere Ciphers
100

the message (written in lowercase letters)

plaintext

100

What is the main goal of cryptography?

secure communications

100

What is 58 mod 12? 

10

100

Which Roman emperor invented a cipher? 

Julius Caesar 

100

How many alphabets does the Vigenere cipher use?

26

200

any general system for hiding the meaning of a message by replacing each letter in the original message with another letter or symbol

cipher

200

What's the difference between steganography and cryptography?

Steganography hides the existence of a message while cryptography hides the meaning of the message

200

What is (3 x 22 + 9) mod 3?

0

200

What is the key for the Caesar cipher?

3

200

There are 25 possible keys for the Shift Cipher? Why not 26?

Because shifting the alphabet 26 spaces puts it back in its original position
300

the science of hiding the existence of a message

steganography

300

Name a type of information you'd want to protect with cryptography.

bank information, medical history, etc. 

300

-27 is equivalent to _____ mod 4 

1

300

The Pigpen Cipher is an example of what kind of cipher?

Substitution cipher

300

Encode the word using a Shift Cipher with key 21. 

secret

NZXMZO

400

the element that turns the general encryption algorithm into a specific method for encryption

key

400

What do both Alice and Bob need in order to communicate with each other using cryptography?

A cipher and a key

400

64 is equivalent to 4 mod 6 since.....

64 = 6 x 10 + 4 

400

Decrypt the message

charity

400

In what year did Babbage propose a way to break the Vigenere Cipher? 

1854

500

the science of secret writing in all its forms

cryptology

500
Name one thing the attacker Eve is trying to do when intercepting a message 

read the message, corrupt the message, etc. 

500

The plaintext letter "r" becomes the number 289 through some encryption process. What is its corresponding ciphertext letter? 

D

500

Encrypt the word using the Caesar Cipher 

peace

SHDFH

500

Decode the word using the Vigenere Cipher with the keyword RED. 

RQHIMFR


america