Unit 2 Data transmission and encryption T4 Encryption

Unit 2 Data transmission and encryption T4 Encryption

By Michael Harrington

Open Ended

Why do you think there is need a for encryption?

Labelling

In symmetric encryption, a key is first shared between the sender and receiver

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Plaintext received

Sender

encryption

Plaintext sent

password

Secret shared key

Encrypted text

Receiver

Open Ended

What happens to the encryption key in symmetric encryption?

Open Ended

In asymmetric encryption, two keys are created by the receiver - what are they called?

Labelling

Asymmetric encryption

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Generated

Lock

Plaintext - Right

Symetric

Public Key

Private Key

Plaintext - Left

Encrypted text

The quick fox

The lazy dog

Multiple Choice

Web pages that are shared using HTTPS make use of encryption - What do these letters stand for?

• Hypertext transfer secure protocol

• Hypertext Harrington protocol secure

• Hyper transfertext protocol secure

• Hypertext transfer protocol secure

Multiple Choice

which is -

encode data into an unreadable form

• Encrypt

• Decrypt

• Public key

• Symmetric encryption

• Asymmetric encryption

Multiple Choice

which is a

a public key is used to encrypt the data; a private key is used to decrypt the data

• Encrypt

• Decrypt

• Public key

• Symmetric encryption

• Asymmetric encryption

Multiple Choice

which is a -

a key that anyone may see and use to encrypt data before it is sent to someone

• Encrypt

• Decrypt

• Public key

• Symmetric encryption

• Asymmetric encryption

Multiple Choice

which is a

decode encrypted data back into plaintext

• Encrypt

• Decrypt

• Public key

• Symmetric encryption

• Asymmetric encryption

Multiple Choice

which is a

a private shared key is used to encrypt and decrypt the data

• Encrypt

• Decrypt

• Public key

• Symmetric encryption

• Asymmetric encryption

Labelling

Asymmetric encryption

Both keys are generated by the receiver

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Red Key

Green Key

Sender

Private key

Plaintext received

Receiver

Public key

Padlock

Encrypted text

Plaintext sent

Reorder

Reorder the following steps as they occur:

See the diagram which shows how asymmetric encryption is used when transmitting a web page from a server to a user using HTTPS.

Each number is a step

• Request the web browser's public key access

• Browser sends public key

• The server combines the web page with the public key to encrypt the web page

• The encrypted page is transmitted

• The web broswer's private key is combined with the encrypted web page to decrypt it

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Open Ended

Find out what the word symmetry means (if you do not know). Now explain how this word symmetry will help you remember which encryption is which.