Unit 2.3 - encryption

Question 1

What is encryption?

Answer 1

Encryption is the process of encoding (scrambling) data using an algorithm so that it becomes unreadable to anyone who does not have the key needed to decrypt the data.

Question 2

What is text that has and has not been encrypted called?

Answer 2

Not encrypted - plain text
Encrypted - cipher text

Question 3

What is the Caesar cipher?

Answer 3

A data encryption method which works by taking the message to be encoded and changing it by shifting each letter in the message a given number of positions either to the left or right. If the receiver wants to decode a message, they must know value and direction of shift.

Question 4

What are the two types of encryption and how do they work?

Answer 4

1. Symmetric encryption - when the same key is used for encrypting and decrypting the message. The key must be sent to receiving computer but separately from the messages. It’s simple and straightforward, but one limitation is that is the key is intercepted, the interceptor would be able to decode the message easily.
2. Asymmetric encryption - when 2 separate keys are used - one for encrypting and the other for decrypting. So, each device (sending or receiving) has 2 keys, private and public. The recipient’s public key is used to encrypt the message, while their private key is used to decrypt the message. The public key should be shared with anyone who wants to send them a message. + much more reliable as the receiver can verify that message came from intended sender, only receiver can read it and private keys do not need to be shared.

Question 5

How can encryption be strengthened?

Answer 5

Increasing the number of possible keys/bits

Question 6

Will encryption prevent unauthorized people to intercept a message?

Answer 6

No, but it will make it difficult for them to understand it.