2.3 Encryption

Question 1

Why is encryption used?

Answer 1

It is used so that data cannot be understood if intercepted without the decryption key.

Question 2

Describe the process of encryption.

Answer 2

• The text before encryption is called plain text.
• The plain text is encrypted using an encryption algorithm.
• The plain text is also encrypted using a key.
• The encrypted text is called ciphertext.
• The key is transmitted separately from the text.
• The key is used to decrypt the ciphertext after transmission.

Question 3

Types of Encryptions?

Answer 3

1) Symmetric encryption
2) Asymmetric encryption

Question 4

How is data encrypted using symmetric encryption?

Answer 4

• The data before encryption is known as plain text.
• To scramble the data, an encryption key & encryption algorithm are used.
• The encryption key & algorithm are applied to plain text to convert it into ciphertext.
• The data after encryption is known as ciphertext, which is meaningless unless the recipient also has the decryption key.
• The same key is used to encrypt and then decrypt the text.
• Encryption prevents the data from being understood by a hacker.

Question 5

How is data encrypted using Asymmetric encryption?

Answer 5

• Uses a matching pair of keys: public and private.
• The public key is shared with everyone.
• The receiver sends their public key to the sender.
• The sender encrypts the message using the receiver’s public key.
• The encrypted message (ciphertext) is sent to the receiver.
• The receiver decrypts it using their private key.
• Only the private key can decrypt data encrypted with its matching public key.

Question 6

What is meant by symmetric encryption?

Answer 6

A single key is used for both encryption and decryption

Question 7

What are 2 drawbacks of using SYMMETRIC ENCRYPTION?

Answer 7

• The key has to be exchanged securely
• Cannot ensure non-repudiation