Encryption is a method of protecting data during data transmission.

1. Data encryption SMS Hasan (Sharqi) (BSc)
Computer Science Teacher - Cambridge Section
Yara International School, Riyadh - KSA
hasan.edu21@gmail.com
+966 57 087 58 28
24-NOV-2021

2. Data encryption
• Internet is world wide network
• We exchange a lot of private data on the internet.
– Email credentials
– Credit card numbers
– Private messages
– Passwords
• It is important to keep the data safe from
eavesdroppers during data transmission.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 2
Keywords
Encryption: is a
method of
protecting data
during the data
transmission.
Eavesdroppers:
The people who
intercept and
read our data
during the data
transmission such
as hackers.

3. What is called data
encryption?
• Data encryption is a process of scrambling data
(message) into human unreadable format before
the transmission takes place.
• This is sometimes called cryptography.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 3
Keywords
Scrambling:
mixing up and
making confusing.
Cryptography: is
the study of
secure
communications
techniques that
allow only the
sender and
intended
recipient of a
message to view
its contents.

4. Data encryption
simulation
Activity:
• Use the simulation tool available in the below
link to find how encryption works really.
https://www.online-toolz.com/tools/text-
encryption-decryption.php
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 4
Keywords
Simulation: is a
way of seeing a
thing happen
without it actually
taking place in
the same way.

5. Data encryption…
• Before the encryption takes place, the data is called
plain-text.
• Then, an encryption algorithm (encryption key) is
applied to the data to scramble and make it
meaningless, this data will be called ciphertext.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 5
Keywords
Plain-text: the
name given to
data before the
encryption
Cipher-text: the
name given to
data after the
encryption
Algorithm: step
by step procedure
to solve a
problem.
plaintext
encryption key
ciphertext

6. Data encryption…
• Now, the ciphertext will be transmitted from
sender to receiver.
• In the end, once the receiver, received the data,
will decrypt the data from ciphertext to plain
text using the decryption key.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 6
Keywords
Sender: the
device which
sends the data
from.
Receiver: the
device which
receives the data
from the sender.
Decryption: the
process of
converting the
data from
ciphertext to
plaintext.

7. Data encryption simulation
Activity:
• Use the simulation tool available in the below
link to find how encryption works really.
https://codebeautify.org/encrypt-decrypt
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 7
Keywords
Simulation: is a
way of seeing a
thing happen
without it actually
taking place in
the same way.

8. Question in context
• Does encryption stop data being stolen by a
hacker?
– No, It will not stop a hacker from stealing the
data, but the data will be unreadable.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 8

9. Types of data encryption
1. Symmetric data encryption.
2. Asymmetric data encryption
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 9

10. Types of data encryption –
1. Symmetric data encryption
1. Symmetric data encryption.
– Uses an encryption key: the same key used to
encrypt and decrypt the data.
Example: 10 digit encryption key.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 10
plaintext
encryption key
ciphertext

11. Data encryption simulation –
Symmetric encryption
Activity:
• Use the simulation tool available in the below
link to find how symmetric encryption works
really.
https://codebeautify.org/encrypt-decrypt
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 11

12. Symmetric data encryption -
Question in context
• Is this enough to keep the data safe?
– No, because in a symmetric encryption, a
single key is shared between sender and the
receiver.
– It is a matter of seconds for the modern
computers to decode an encrypted message
using a single key.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 12
Keywords
Decode:
Metaphor of the
decryption.

13. 2. Asymmetric data encryption.
– Uses different keys for encrypting and
decrypting the data.
• Public key = (Available for everyone)
• Private key = (Only available for the receiver’s
computer)
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 13
Keywords
Public key: a key
which is made
available by the
receiver to the
sender to send
the data.
Private key: a key
which is available
in the receiver’s
computer only to
decrypt the data
that arrived from
the sender.
Step 01 Step 02
Types of data encryption –
2. Asymmetric data encryption

14. Data encryption simulation –
Asymmetric encryption
Activity:
• Use the simulation tool available in the below
link to find how asymmetric encryption works
really.
https://www.javainuse.com/rsagenerator
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 14

15. Asymmetric data encryption -
Question in context
• Is this enough to keep the data safe?
– This method is more than enough to keep the data
safe because the private key will be available only on
the receiver's computer which is used to decrypt the
message.
– The senders will send the message to the receivers
using public key only, no one knows the receiver’s
private key.
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 15

16. Q & A
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 16

17. Thank you
5-Jan-23 SMSHasan (Sharqi) (BSc) | hasan.edu21@gmail.com | +966 57 087 5828 17