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Cryptography & Network Security (CNS) AKTU exam strategy

Focus on Unit 2 (Mathematical Foundations, AES and Public Key Cryptography) and Unit 1 (Security Foundations, Classical Encryption and Modern Block Ciphers). Together they account for about 61 marks among all questions printed per paper. Unit 5 (IP Security, Secure Transactions and System Security) is safest to skim if you're short on time.

Unit priority

  • Unit 2 (Mathematical Foundations, AES and Public Key Cryptography) – Must Prepare, 32 marks avg. Unit 2 (Mathematical Foundations, AES and Public Key Cryptography) averages 32 marks per paper — one of the heaviest units in this subject. Must-do: Extended Euclidean Algorithm, Chinese Remainder Theorem, Advanced Encryption Standard (AES), Euler Theorem.
  • Unit 1 (Security Foundations, Classical Encryption and Modern Block Ciphers) – High Priority, 29 marks avg. Unit 1 (Security Foundations, Classical Encryption and Modern Block Ciphers) averages 29 marks per paper — one of the heaviest units in this subject. Must-do: Classical Encryption Techniques, Data Encryption Standard (DES), Block Cipher Modes of Operation, Security Services.
  • Unit 4 (Key Distribution, Authentication Applications and Email Security) – High Priority, 28 marks avg. Unit 4 (Key Distribution, Authentication Applications and Email Security) averages 28 marks per paper — one of the heaviest units in this subject. Must-do: Kerberos, X.509 Certificates, Diffie-Hellman Key Exchange, Pretty Good Privacy (PGP).
  • Unit 3 (Message Authentication, Hash Functions and Digital Signatures) – Medium Priority, 26 marks avg. Unit 3 (Message Authentication, Hash Functions and Digital Signatures) averages 26 marks per paper — one of the heaviest units in this subject. Secure Hash Algorithm (SHA) has appeared in every paper analysed — these are must-dos. Must-do: Secure Hash Algorithm (SHA), Digital Signatures, Message Authentication Codes, Hash Functions.
  • Unit 5 (IP Security, Secure Transactions and System Security) – Safe to Skim, 22 marks avg. Unit 5 (IP Security, Secure Transactions and System Security) averages 22 marks per paper — one of the heaviest units in this subject. Must-do: IP Security, Intrusion Detection, Secure Electronic Transaction (SET), Secure Socket Layer.

Topics AKTU keeps repeating

  • Secure Hash Algorithm (SHA): Asked in 9 out of 10 papers. If you prepare only one topic from its unit, make it this one.
  • Extended Euclidean Algorithm: Asked in 8 out of 10 papers. If you prepare only one topic from its unit, make it this one.

Short on time?

  • Among all units, Unit 5 (IP Security, Secure Transactions and System Security) is the lowest priority at 22M avg. If you're running low on time, prioritize the top 3 units and give this one a quick read. But even here — IP Security, Secure Electronic Transaction (SET), Intrusion Detection are high-repeat topics. Cover these at minimum to stay safe.

How the paper is marked

  • Section A: 7 questions × 2 marks = 14 marks. Short definition/concept questions from all 5 units. Prepare 2–3 key definitions per unit — this section is the easiest 14 marks you can secure.
  • Section B: Attempt any 3 of 5 questions × 7 marks = 21 marks. Choose the 3 questions from units you've prepared most. Don't attempt all 5 — pick your strongest 3 and write them well.
  • Section C: 5 OR-pairs × 7 marks = 35 marks. One pair per unit — you must attempt all 5. This is where the exam is won or lost. Focus your deep preparation on the top 3 priority units.

Exam-day tips

  • Start with Section A to build momentum — budget 15–20 minutes max for all 7 questions.
  • In Section B, Unit 2 (Mathematical Foundations, AES and Public Key Cryptography) questions have the highest repeat rate — always attempt that one first.
  • For Section C OR-pairs, read both options before choosing — sometimes the 'b' option is simpler despite appearing longer.
  • If you've prepared the VERY LIKELY topics, you can comfortably score 50+ marks without touching any new topic on exam day.
  • This strategy is built on 10 past papers — the patterns here are highly reliable.