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WorksheetsCryptography and Ciphers Redo 2
Total questions: 25
Worksheet time: 13mins
What is the main feature of a Caesar Shift Cipher?
It substitutes each letter for another letter from a fixed alphabet.
It uses a keyword for multiple substitution alphabets.
It replaces a letter with another letter a fixed number of positions away in the alphabet.
It rearranges the letters without changing them.
Which cipher uses multiple substitution alphabets based on a keyword?
Simple Substitution Cipher
Caesar Shift Cipher
Playfair Cipher
Vigenere Cipher
What is the main goal of Steganography?
To scramble a message to make it unreadable to unauthorized parties.
To hide the existence of the message itself.
To replace pairs of letters with different pairs of letters.
To use frequency analysis to break the encryption.
The Scytale is an example of what type of classical cipher?
Substitution Cipher
Transposition Cipher
Homophonic Cipher
Polygraphic Cipher
Which statement best describes the Pigpen Cipher?
Polyalphabetic cipher using a shifting key.
Homophonic cipher using multiple symbols per letter.
Simple substitution cipher that uses symbols (or geometric shapes) instead of letters.
Block cipher that operates on 64-bit blocks.
What makes the Playfair Cipher different from a Simple Substitution Cipher?
It uses a one-time pad.
It encrypts digraphs (pairs of letters) instead of single letters.
It requires a cylindrical device for encryption.
It uses a new, random substitution for every character.
What does a Simple Substitution Cipher replace?
Single letters with a single, unique, corresponding plaintext letter.
Single letters with a single, unique, corresponding ciphertext letter.
Blocks of bits with a block of encrypted bits.
Digraphs with digraphs.
Why is a Homophonic Substitution Cipher difficult to solve?
Make the encryption process faster for computers.
Obscure the frequency distribution of letters in the plaintext.
Allow the use of non-alphabetic characters in the ciphertext.
Encrypt an entire word or phrase as a single unit.
Blowfish is classified as a:
Stream Cipher
Block Cipher
Transposition Cipher
Substitution Cipher (Historical)
The Playfair Cipher is an example of a:
Simple Substitution Cipher
Polyalphabetic Cipher
Homophonic Substitution Cipher
Polygraphic Substitution Cipher
Hannah and Isla use a Caesar Shift cipher with a key of 3. If Isla writes D, what letter does Hannah see in the ciphertext?
A
G
D
E
Who designed the Blowfish algorithm?
Alan Turing
Bruce Schneier
Leonardo da Vinci
Julius Caesar
Why is a Polyalphabetic Cipher better than a Simple Substitution Cipher for keeping messages safe?
It is much faster to encrypt and decrypt manually.
It can use numbers and symbols as well as letters.
It makes frequency analysis much more difficult to use.
It does not require a key to be shared between sender and receiver.
What determines the key for a Scytale cipher?
Length of the keyword used for substitution.
Diameter of the cylinder/rod used.
Number of symbols used in the final ciphertext.
Specific pre-selected substitution table.
Which of the following is NOT a steganography trick?
Hiding a message in the least significant bits of an image file.
Writing an invisible message using lemon juice as ink.
Encrypting a message using a Vigenere cipher.
Hiding a message in a text by making the first letter of each word spell out the secret.
Is the Caesar Shift Cipher a type of Polyalphabetic Cipher? Select True or False.
True
False
Select True or False: A Homophonic Substitution Cipher assigns multiple ciphertext characters to one plaintext character.
True
False
Is the Pigpen Cipher a modern symmetric-key algorithm? True or False.
True
False
Steganography is the process of scrambling a message so only the intended recipient can read it. True or False?
True
False
Is the Playfair Cipher a Polygraphic Cipher because it encrypts letters in pairs (digraphs)? Select True or False.
True
False
Choose the term: A ____ cipher uses a keyword to change the substitution alphabet for each letter in the plaintext.
Vigenère
Caesar
Atbash
ROT13
Choose the term: The ____ cipher used a cylindrical rod to wrap parchment for encryption and decryption.
Scytale
Rail Fence
Columnar Transposition
Pigpen
Which modern symmetric block cipher was designed by Bruce Schneier?
Blowfish
AES
DES
RC4
Which cipher replaces two or more plaintext characters with a block of two or more ciphertext characters?
Monoalphabetic
Polyalphabetic
Polygraphic
Homophonic
Choose the term that best completes the sentence: The core principle of a ____ cipher is to replace every instance of a plaintext character with the same ciphertext character throughout the message.
Monoalphabetic
Polyalphabetic
Transposition
Stream
