Year 8 ICT Assessment

What is encryption?

• When you put data / text into code making it difficult to read or understand.

• A secret or disguised way of writing; a code.

• A formal language designed to communicate instructions to a machine

• What is put in, taken in, or operated on by any process or system.

Answer explanation

The correct choice defines encryption as the process of converting data or text into a code, making it difficult to read or understand. This accurately captures the essence of encryption, which is to protect information.

A cipher is _________________________.

• a person who makes up secret codes

• an algorithm that is used to scramble text so that it can be passed in secret

• a lock that can be used to lock a message in a lock box

• any puzzle, such as a crossword or Sudoku puzzle

Answer explanation

A cipher is specifically an algorithm used to scramble text, making it unreadable to unauthorized users. This definition distinguishes it from other options, such as a person or a physical lock, which do not accurately describe a cipher.

Who was the first known user of the Caesar Cipher?

• Caesar Romanus

• Julius Caesar

• Alan Turing

• There isn't one

Answer explanation

The Caesar Cipher is named after Julius Caesar, who is the first known user of this encryption technique to protect military messages. Thus, the correct answer is Julius Caesar.

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

• Simple Text

• Plain Text

• Cipher Text

• Filled Text

Answer explanation

In Cryptography, the original message before transformation is known as 'Plain Text'. It is the readable form of the message, while 'Cipher Text' refers to the encrypted version.

An encryption algorithm transforms plain text into:

• Cipher text

• Simple Text

• Empty Text

• Plain Text

Answer explanation

An encryption algorithm transforms plain text into cipher text, which is the encoded version of the original message, making it unreadable without the proper decryption key.

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

• Cryptography

• Cryptoanalysis

• neither Cryptography nor Cryptoanalysis

• either Cryptography or Cryptoanalysis

Answer explanation

Cryptography is the science and art of transforming messages to secure them against attacks. It focuses on creating secure communication methods, while cryptoanalysis deals with breaking those secure methods.

A(n) ______ algorithm transforms cipher text to plain text.

• Encryption

• Decryption

Answer explanation

A decryption algorithm is specifically designed to convert cipher text back into plain text, reversing the encryption process. Therefore, the correct answer is 'Decryption'.

A Caesar cipher is an example of a ______________________.

• transposition cipher

• bimodal cipher

• substitution cipher

• substantial cipher

Answer explanation

A Caesar cipher is a type of substitution cipher because it replaces each letter in the plaintext with a letter a fixed number of positions down the alphabet, rather than rearranging the letters as in a transposition cipher.

Encrypt the word alphabet using a Caesar cipher with a shift of 3

• DVSDULQV

• DOOFOHDU

• DOSKDEHW

• DORQHBHV

Answer explanation

To encrypt 'alphabet' using a Caesar cipher with a shift of 3, shift each letter 3 places forward: a->d, l->o, p->s, h->k, a->d, b->e, e->h, t->w. This results in 'DOSKDEHW', which is the correct answer.

The process of converting a ciphertext into plaintext.

• encryption

• decryption

• plaintext

• cryptography

Answer explanation

The process of converting ciphertext back into plaintext is called decryption. In contrast, encryption is the process of converting plaintext into ciphertext. Therefore, the correct answer is decryption.