Terminology
the message (written in lowercase letters)
plaintext
What is the main goal of cryptography?
secure communications
What is 58 mod 12?
10
Which Roman emperor invented a cipher?
Julius Caesar
How many alphabets does the Vigenere cipher use?
26
any general system for hiding the meaning of a message by replacing each letter in the original message with another letter or symbol
cipher
What's the difference between steganography and cryptography?
Steganography hides the existence of a message while cryptography hides the meaning of the message
What is (3 x 22 + 9) mod 3?
0
What is the key for the Caesar cipher?
3
There are 25 possible keys for the Shift Cipher? Why not 26?
the science of hiding the existence of a message
steganography
Name a type of information you'd want to protect with cryptography.
bank information, medical history, etc.
-27 is equivalent to _____ mod 4
1
The Pigpen Cipher is an example of what kind of cipher?
Substitution cipher
Encode the word using a Shift Cipher with key 21.
secret
NZXMZO
the element that turns the general encryption algorithm into a specific method for encryption
key
What do both Alice and Bob need in order to communicate with each other using cryptography?
A cipher and a key
64 is equivalent to 4 mod 6 since.....
64 = 6 x 10 + 4
Decrypt the message
charity
In what year did Babbage propose a way to break the Vigenere Cipher?
1854
the science of secret writing in all its forms
cryptology
read the message, corrupt the message, etc.
The plaintext letter "r" becomes the number 289 through some encryption process. What is its corresponding ciphertext letter?
D
Encrypt the word using the Caesar Cipher
peace
SHDFH
Decode the word using the Vigenere Cipher with the keyword RED.
RQHIMFR
america