CRYPTOGRAPHY

DONE BY: WU CHU JUN

INTAN SYAZWANI BTE JA’AFAR

MINDY SOH XI LIN

ENCRYPTION & DECRYPTION KEY USED IN REAL LIFE• Internet browsing has encryption to secure traffic

between user and the site.

• Encryption is used in ATM cards, account passwords

and electronic mails

•Used for file protection

•When one’s operating software automatically updates

over the Internet, it too will use a public key algorithm

to confirm the source of the software being updated

from, and not just someone trying to get into their

computer.

HOW MATHEMATICS HAS A PART TO PLAY IN THIS PROCESS

•Using mathematical formulas or functions

applied to the data to transform the

unprotected information or plaintext, into an

undecipherable format known as ciphertext.

•Having numbers used in encryption and

decryption keys makes it more secure to deliver

information from one party to another, thus

any third party who has access to the hidden,

encrypted data cannot deconstruct or decrypt

WHY DO WE NEED CRYPTOGRAPHY?

• If one does not use encrypted connection with

the server, anyone can get their hands on any

unsecured resources.

•For example, Wi-Fi is vulnerable to what they

call, “eavesdroppers” that are able to review raw

packets from a file sent over the network, and

gain access to contents of clear-text files.

OUR METHOD

• Thus, we would want to distort the original text into an

unreadable one, using mathematical formulas such as scaling,

translation and rotation about 90o in an anti-clockwise

direction.

We decided to implement what we have learnt from chapter 1

(Matrices) and 2 (Linear Transformation). We consider the

message as a graph, thus using the linear transformation

formulas provided.

OPERATION RED CAT TABLE

ENCRYPTION KEY

• Rotation about

90o in an anti-

clockwise

direction (T1)

100

020

002

100

001

010

100

910

601

• Scaling (T2) • Translation (T3)

100

1802

1220

Encryption Key = (T3T2T1)

DECRYPTION KEY

• Rotation about

90o in an anti-

clockwise

direction (T1)

100

001

010

100

910

601

100

05.00

005.0

100

605.0

95.00

• Scaling (T2) • Translation (T3)

Decryption Key = (T1-1T2

-

1T3-1)

PROCESS

•Message: Maths Project :(

11111111

)(:

()()(

nullteoPha

spacecjrspacetM

11111111

02145258573467

70237563524584

*Matrix of message based on Operation Red Cat table

ENCRYPTION PROCESS

100

1802

1220

11111111

02145258573467

70237563524584

11111111

15822921308822108186

12307838158134802

DECRYPTION PROCESS

100

605.0

95.00

11111111

15822921308822108186

12307838158134802

11111111

02145258573467

70237563524584

TA-DAAAA!

• Referring back to the Operation Red Cat

table… message decrypted: Maths Project

:(

11111111

)(:

()()(

nullteoPha

spacecjrspacetM

11111111

02145258573467

70237563524584

THANK YOU FOR YOUR ATTENTION!