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

• Copy

• scramble

• delete

• solve

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

• Send

• key

• decryption

• cipher

The original message is sometimes called--------- , and the encrypted message is sometimes called------------

• plaintext

• algorithm

• key

• ciphertext

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.

• cipher

• key

• algorithm

• spoon

---

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

• transmission

• cipher

• plaintext

• decipher

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

• ejfd

• gtyj

• yzxp

• vbuk

Decrypt this ciphertext message: HKRVH

• spies

• Pies

• cooks

• paint

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

• true

• false