Bsc Csit Nepal

Cryptography

Course Description:

The course introduces the underlying the principles and design of cryptosystems. The course covers the basics concepts of cryptography including: traditional ciphers, block ciphers, stream ciphers, public and private key cryptosystems. The course also includes the theory of hash functions, authentication systems, network security protocols and malicious logic.

Course Objectives:

The objectives of this course are to familiarize the students with cryptography and its applications. The students will be able to develop basic understanding of cryptographic mechanisms.

Course Contents:

Unit 1: Introduction and Classical Ciphers (7 Hrs.)

  • 1.1. Security: Computer Security, Information Security, Network Security, CIA Triad: Confidentiality, Integrity, Availability, Cryptography, Cryptosystem, Cryptanalysis, Security Threats:, Attacks: Passive (Release of message, Traffic analysis), Active (Replay, Denial of service) Security Services: Authentication, Access Control, Nonrepudiation Security Mechanisms, Policy and Mechanism

  • 1.2. Classical Cryptosystems: Hierarchy of cipher Substitution Techniques:

    • Monoalphabetic: Ceasar Cipher, Hill
    • Polyalphabetic: Vigenere Cipher (Variants: vernam, one time pad), Playfair Transposition Techniques: Rail Fence Cipher

  • 1.3. Modern Ciphers: Block Ciphers, Stream Ciphers,Symmetric Ciphers, Asymmetric Ciphers

Unit 2: Symmetric Ciphers (10 Hrs.)

  • 2.1. Fiestel Cipher Structure, Substitution Permutation Network (SPN)
  • 2.2 Data Encryption Standards (DES): Key Generation, Encryption and Decryption Process, Weak Keys in DES, Double DES, Meet in Middle Attack, Triple DES
  • 2.3. Finite Fields: Basic concepts of Groups, Rings, and Fields, GCD, Euclidean Algorithm, Modular Arithmetic, Set of Residue (Zn), Congruence, Residue classes, Quadratic residue, Operations on Zn (Addition, Subtraction, Multiplication), Properties of Zn, Inverses: Additive Inverse, Multiplicative Inverse, Relatively Prime, Extended Euclidean Algorithm, Galois Fields (GF(p) & GF(2n)), Polynomial Arithmetic : Addition, Multiplication and Division over Galois Field
  • 2.4. International Data Encryption Standard (IDEA): Key Generation, Encryption and Decryption Process
  • 2.5. Advanced Encryption Standards (AES): Key Generation, Encryption and Decryption Process
  • 2.6. Modes of Block Cipher Encryptions (Electronic Code Book, Cipher Block Chaining, Cipher Feedback Mode, Output Feedback Mode, Counter Mode)

Unit 3: Asymmetric Ciphers (8 Hrs.)

  • 3.1. Number Theory: Prime Numbers, Primality Testing, Miller-Rabin Algorithm,Fermat’s Theorem, Euler’s Totient Function andEuler’s Theorem, Primitive Root, Discrete Logarithms
  • 3.2. Public Key Cryptosystems, Applications of Public Key Cryptosystems
  • 3.3. Distribution of public key, Distribution of secret key by using public key cryptography, Diffie- Hellman Key Exchange, Man-in-the-Middle Attack
  • 3.4. RSA Algorithm: Key Generation, Encryption and Decryption Process
  • 3.5. Elgamal Cryptographic System: Key Generation, Encryption and Decryption Process

Unit 4: Cryptographic Hash Functions and Digital Signatures (8 Hrs.)

  • 4.1. Message Authentication, Message Authentication Functions, Message Authentication Codes
  • 4.2. Hash Functions, Properties of Hash functions, Applications of Hash Functions
  • 4.3. Message Digests: Details of MD4 and MD5 algorithms
  • 4.4 Secure Hash Algorithms: Details of SHA-1 and SHA-2 algorithms, Comparison of SHA parameters, SHA-512
  • 4.5. Digital Signatures: Direct Digital Signatures, Arbitrated Digital Signature
  • 4.6. Digital Signature Standard: The DSS Approach, Digital Signature Algorithm(DSA)
  • 4.7. Digital Signature Standard: The RSA Approach

Unit 5: Authentication (3 Hrs.)

  • 5.1. Authentication System,
  • 5.2. Password Based Authentication, Dictionary Attacks (Online and Offline),
  • 5.3. Challenge Response System, One Way Authentication, Mutual Authentication
  • 5.4. Biometric System
  • 5.5. Needham-Schroeder Scheme, Kerberos Protocol, Kerberos 5

Unit 6: Network Security and Public Key Infrastructure (6 Hrs.)

  • 6.1. Overview of Network Security
  • 6.2. Digital Certificates and X.509 certificates, Certificate Life Cycle Management
  • 6.3. PKI trust models, PKIX
  • 6.4. Email Security: Pretty Good Privacy (PGP), Services provided by PGP
  • 6.5. Secure Socket Layer (SSL) Protocol
  • 6.6. Transport Layer Security (TLS) Protocol
  • 6.7. IP Security (IPSec) Protocol
  • 6.8. Firewalls, Firewall Characteristics, Types of Firewalls: Packet filtering firewall, Circuit-level gateway, Stateful inspection firewall, Proxy firewall, Next-generation firewall

Unit 7: Malicious Logic (6 Hrs)

  • 7.1.Malicious Logic, Types of Malicious Logic: Virus, Worm, Trojan Horse, Zombies, Denial of Service Attacks,
  • 7.2. Intrusion, Intruders and their types (Masquerader, Misfeasor, Clandestine),Intrusion Detection System: Statisticalanomaly detection, Rule-based detection

Laboratory Work Manual:

Student should write programs and prepare lab sheet for all of theunits in the syllabus. Students should implement cryptographic algorithmsand protocols mentioned in each. The choice of programming language can be decided by the instructor and student as per their comfort. The instructors have to prepare lab sheets for individual units covering the concept of the units as per the requirement. All of the lab reports should be evaluated during the corresponding weeks of hands on practice. The lab session for above chapters should be as per following description however the depth of lab works are not limited to the below mentioned contents only. The lab report might cover the following list of the programs.

Write the program to illustrate the followings

  • Monoalphabetic Ciphers: Ceasar, Hill
  • Polyalphabetic Cipher: Vigenere Cipher (Vernam, OTP), Playfair
  • Transposition Cipher: Rail Fence Cipher
  • Some basic components of DES like functioning of S-Box, Key generation
  • Modular Arithmetic (Finding additive inverse, multiplicative inverse (Extended Euclidean algorithm, relatively prime)
  • Number Theory (Primality testing, Totient function, Primitive root)
  • Diffie-Helman Key Exchange, RSA Algorithm, Elgamal Cryptographic System
  • Some basic logic for Malicious code

Text Books:

  1. W. Stallings, Cryptography and Network Security: Principles and Practice
  1. William Stallings, Network Security Essentials: Applications and Standards
  2. Matt Bishop, Computer Security, Art and Science.
  3. Mark Stamp, Information Security: Principles and Practices.
  4. Bruce Schneier, Applied Cryptography.
  5. Douglas. R. Stinson. Cryptography: Theory and Practice.
  6. B. A. Forouzan, Cryptography & Network Security, Tata Mc Graw Hill.