Encryption

What is the purpose of encryption?

• • To hide the sender's identity

• • To protect data from unauthorized access

• • To increase internet speed

• • To compress files

There are two main types of encryption: _____ ___ _____ （use lower case)

What is the most widely used asymmetric encryption algorithm?

• DES (Data Encryption Standard)

• AES (Advanced Encryption Standard)

• RSA (Rivest-Shamir-Adleman)

• Blowfish

If there’s no lock in the address bar and the web address says HTTP without an S, that means every bit of data you send is private and safe.

• True
• False

Today's secure communications are encrypted using ______ bit keys.

• 156

• 10

• 356

• 256

Explain some differences between plain text and cipher text.

If you were to use a caeser cipher with a key of 3 shifts to the left, how would you encrypt the word: Cipher?

• ZAMEBO
• ZOMEBO
• ZFMEBO
• ZFMEBA

Consider the process of encoding and decoding a message using the following Caesar cipher encoding scheme in which the plaintext and ciphertext alphabets are offset by four positions, as shown below:

^{Plaintext: a b c d e f g h i j k l m n o p q r s t u v w x y z}

^{Ciphertext: w x y z a b c d e f g h i j k l m n o p q r s t u v}

Which of the following encoded ciphertext strings decodes to an original plaintext message of "secret"?

• etsecr

• wigvix

• kwujwl

• oaynap

1. What is the main feature of asymmetric encryption?

• 1. It uses a pair of keys, one of which is public and the other private, to encrypt and decrypt messages.

• 1. It uses a single key to encrypt and decrypt messages.

• 1. It can ensure the authenticity of the sender and the confidentiality of the message.

• 1. It can protect against unauthorized access to the message.

1. What is the main advantage of symmetric encryption?

• 1. It can encrypt large amounts of data quickly and efficiently.

• 1. It can ensure the authenticity of the sender and the confidentiality of the message.

• 1. It can be used for both encryption and decryption using the same key.

• 1. It can provide better security than asymmetric encryption.