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

Course syllabus Name of faculty member : TA.Maram AlMuhareb Email : Ma.abdulaziz1@gmail.com Office : 0.701.01 1-Dec-18 Networks and Communication Department

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

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

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

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

Recalling Networks and Communication Systems Department

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

Cryptography Categories Networks and Communication Systems Department

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

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

Questions Traditional Ciphers Networks and Communication Systems Department

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 00 M 12 Y 24 B 01 N 13 Z 25 C 02 O 14 D 03 P 15 E 04 Q 16 F 05 R 17 G 06 S 18 H 07 T 19 I 08 U 20 J 09 V 21 K 10 W 22 L 11 X 23   GOVMYWO TUJS YMJ ITTW Networks and Communication Systems Department

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 00 M 12 Y 24 B 01 N 13 Z 25 C 02 O 14 D 03 P 15 E 04 Q 16 F 05 R 17 G 06 S 18 H 07 T 19 I 08 U 20 J 09 V 21 K 10 W 22 L 11 X 23   1-Dec-18 Networks and Communication Systems Department

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

Q4: Transposition cipher The following text was encrypted using the transposition cipher with the following mapping as the key, decrypt the message : 1 2 3 4 5 Decrypt Encrypt HI SARA I HOPE YOU ARE FINE LOOKING FORWARD TO SEE YOU Cipher Text: SAHRIHOAPIOUEAYFIRNEOOEKLGFIONARRDWSETEOUZYZO

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

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