• To gain knowledge about the mathematics of the cryptographic algorithms 
  • To get an insight into the working of different existing cryptographic algorithms 
  • To learn how to use cryptographic algorithms in security 



  • Able to  understand the basic concepts of symmetric cryptosystem, public key cryptosystem and digital signature scheme 
  • Able to reason about the security of cryptographic constructions
  • Able to break the cryptosystems that are not secure 


Unit – I

Number Theory:  Fermat's theorem, Cauchy 's theorem, Chinese remainder theorem, Primality testing algorithm,   Euclid's algorithm for integers,  quadratic residues, Legendre symbol,  Jacobi symbol


Unit – II

Cryptography  and  cryptanalysis,  Classical  Cryptography, different  type of attack: CMA, CPA, CCA etc.,  Shannon perfect secrecy,  OTP, Pseudo random bit generators,  stream ciphers  and RC4 .


Unit – III

Block ciphers: Modes of operation, DES and its variants, finite fields (2n), AES, linear and differential cryptanalysis 


Unit – IV

One-way function, trapdoor one-way function, Public key cryptography, RSA cryptosystem, Diffie-Hellman key exchange algorithm, ElGamal Cryptosystem 


Unit – V

Cryptographic hash functions, secure hash algorithm, Message authentication, digital signature, RSA digital signature 



  1. Stinson. D. Cryptography: Theory and Practice, 3rd edition, Chapman & Hall/CRC, 2012 


  1. W. Stallings,”Cryptography and  Network Security Principles and practice”, 5/e, Pearson Education Asia, 2013 
  2. Behrouz A. Forouzan  and  Debdeep Mukhopadhyay, “Cryptography and Network Security”, 2nd edition, Tata McGraw Hill, 2013 
  3. Thomas Koshy, “Elementary Number Theory with Applications”, Elsevier India, 2005 
  4. Online course: course on cryptography by Dan Boneh