Quiz 4: Internet safety, cyber security and encryption

The word 'encryption' means to --------- a message so that no one else can understand it.

• solve

• copy

• delete

• scramble

The word ------------- means to unscramble a message so that it makes sense again.

• decryption

• key

• encryption

• send

A message is a type of encryption. Knowing which ---------- was used is essential if you want to turn it back into a readable message.

• Transmission

• cipher

• message

• plain text

The original message is sometimes called plain text , and the encrypted message is sometimes called ------------ .

• algorithm

• ciphertext

• key

• message

The -------- is a special value used in encryption. Knowing this value should make it easy to decrypt a message. Not knowing it should make it very difficult.

• key

• algorithm

• cipher

True or false? The Atbash Cipher uses a key, which the person receiving the message must use to decrypt it.

• True

• False

True or false? When using the Atbash Cipher, the letters of the alphabet are written out twice, once forwards and once backwards.

• True

• False

Encrypt this plaintext message: BACK

(a)  

Decrypt this ciphertext message: HKRVH

(a)  

True or false? The Caesar Cipher uses a key which the person receiving the message must use to decrypt it.

• True

• False