1. NET 311D Information Security
Networks and Communication Systems Department
TA. Anfal AlHazzaa
TUTORIAL 1 (Traditional Ciphers “Character-oriented”)

2. Course syllabus Name of faculty member : TA.Maram AlMuhareb
Office :
1-Dec-18
Networks and Communication Department

3. Intended learning outcomes
Lab Contents
Assessment methods
Intended learning outcomes
Activity
Topic
Week -
Introduction to the course content (tutorial part) 2
- Assignment
- Participation
-The ability to demonstrate the basic knowledge of Information Security.
-The ability to solve problems related to the traditional ciphers.
- Exercise solving
- Lecture discussion
Exercises on Lecture 2 (Traditional Ciphers). 3
1-Dec-18
Networks and Communication Department

4. Lab Contents - Assignment - Participation
-The ability to solve problems related to the substitution and transposition ciphers
- Exercise solving
- Lecture discussion
Exercises on Lecture 2 cont. (Simple modern ciphers). 4
-The ability to solve a real DES example.
Lecture 3 extension: How DES Works in Detail. 5
-The ability to solve RSA exercises.
Exercises on lecture 4 ( RSA ). 6
-Practical assignment
-Encrypt and decrypt a message practically using GPG4WIN.
-Lab work
Using GPG4WIN to encrypt and decrypt a message. 7
1-Dec-18
Networks and Communication Department

5. Lab Contents -Practical assignment
-Sign a message practically using GPG4WIN.
- Lecture discussion
-Lab work
Using GPG4WIN to apply the digital signature. 8
- Learn how to secure the OS using different ways.
How to secure your system (ex. Windows 8). 9 10
-Learn how to use one of the anti-malware software practically.
Using one of the anti-malware software( ex. Hijackthis). 11 -
Free topic 12
Project Discussion
13-14
1-Dec-18
Networks and Communication Department

6. تقسيم الدرجات للجزء العملي – Grade distribution (Tutorial part)
Percentage from overall grade
Grade
Assessment week
Assessment method 8% 8
10, 12
Lab assignments (2 Sheets) 2% 2
weekly
Participation
10% 10 13
Programming project
20%
Total
1-Dec-18
Networks and Communication Department

7. Recalling
Networks and Communication Systems Department

8. Example Networks and Communication Systems Department
Plaintext : original message before being transformed.
Ciphertext : The message after transformation (coded).
Cipher : algorithm for transforming plaintext to ciphertext
Key : information used in cipher known only to sender/receiver
Encrypt : converting plaintext to ciphertext
Decrypt: recovering ciphertext from plaintext
Cryptography : study of encryption principles/methods
Cryptanalysis (codebreaking) - study of principles/ methods of decrypting ciphertext without knowing key
Networks and Communication Systems Department

9. Cryptography Categories
Networks and Communication Systems Department

10. Symmetric Key Symmetric Key Traditional Ciphers Symmetric Key
Modern Round Ciphers
Traditional Ciphers
Simple Modern Cipher
Networks and Communication Systems Department

11. Traditional Ciphers Shift (Caesar) cipher
Networks and Communication Systems Department

12. Questions Traditional Ciphers
Networks and Communication Systems Department

13. Q1: Substitution cipher (Caesar)
Encrypt the following texts using the shift (Caesar) cipher with the keys in brackets:
“Welcome” (Key=10)
GOVMYWO
“Open the door” (Key=5)
TUJS YMJ ITTW
A M Y 24
B N Z 25
C O 14
D P 15
E Q 16
F R 17
G S 18
H T 19
I U 20
J V 21
K W 22
L X 23
GOVMYWO
TUJS YMJ ITTW
Networks and Communication Systems Department

14. Q2: Substitution cipher (Caesar)
Alice wants to encrypt a message to Bob by using the shift cipher algorithm “Caesar cipher” and the key= 20.
The plaintext = “QUIZ”.
( Hint: you may need to use the table)
Answer:
KOCT
A M Y 24
B N Z 25
C O 14
D P 15
E Q 16
F R 17
G S 18
H T 19
I U 20
J V 21
K W 22
L X 23
1-Dec-18
Networks and Communication Systems Department

15. Q3: Substitution cipher (Monoalphbetic)
Use the following table as the key to encrypt the following texts using the substitution cypher:
“Announce it tomorrow”
EVVRYVZH BF FRDRWWRX
- “DO IT”
- JR BF A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Networks and Communication Systems Department

16. Q4: Transposition cipher
The following text was encrypted using the transposition cipher with the following mapping as the key, decrypt the message :
Decrypt
Encrypt
HI SARA I HOPE YOU ARE FINE LOOKING FORWARD TO SEE YOU
Cipher Text:
SAHRIHOAPIOUEAYFIRNEOOEKLGFIONARRDWSETEOUZYZO

17. Q4: Transposition cipher cont.
Answer
HI SARA I HOPE YOU ARE FINE LOOKING FORWARD TO SEE YOU
Networks and Communication Systems Department

18. Q5: Transposition cipher
Encrypt the following message using transposition cipher based on the key shown below:
The message is “SWEET HEART”.
Answer:
WESTHEAREZZT
Networks and Communication Systems Department