## About the course

This course covers all the fundamental concepts of Cryptography and Network Security. In this course, you will be introduced to the areas of cryptography and cryptanalysis. You will get an overview of modern cryptography along with an introduction to number theory. After that, you will learn about probability and information theory, classical cryptosystems, cryptanalysis of classical ciphers. Then you will learn about Shannon's theory followed by symmetric key ciphers, block ciphers standards, linear and differential cryptanalysis, stream ciphers, cryptographic hash functions and a lot more. This is completely an online course, and you can access it from anywhere in the world. So, this makes it all together a complete package.

##### Learning Outcomes

After completing this course, you will be able to:

- Know about various encryption techniques.
- Understand and illustrate various Public key cryptographic techniques.
- Understand about message authentication and hash functions.
- Boost your hireability through innovative and independent learning.
- Get a certificate on successful completion of the course.

##### Target Audience

The course can be taken by:

**Students:** Students: All students who are pursuing any technical/professional courses, and wish to learn cryptography techniques.

**Teachers/Faculties:** All teachers/faculties who wish to acquire new skills or improve their efficiency in Cryptography.

**Professionals:** All working professionals, who want to enhance their skills by learning cryptography techniques.

##### Why learn Cryptography and Network Security?

With the advent of the World Wide Web and the emergence of e-commerce applications and social networks, organizations across the world generate a large amount of data daily. Data security is the utmost critical issue in ensuring the safe transmission of information through the internet. Also, network security issues are now becoming important as society is moving towards digital information age. As more and more users connect to the internet it attracts a lot of cyber-criminals. It comprises authorization of access to information in a network, controlled by the network administrator. The task of network security not only requires ensuring the security of end systems but of the entire network.

In today's world, crypto professionals are in great demand both within the government and private sector. NSA, FBI, CIA, think tanks and other federal government and defense and intelligence contractors are always on the lookout to hire these individuals. Companies offering encryption, digital data services, and authentication tools are heavy in hiring crypto and security practitioners. The demand across all industries for increased computer security is growing, and cryptography is a subcategory within the career field of information security. Cryptologists are in demand in the military forces, government agencies, technology companies, banking and financial organization s, law enforcement agencies, universities, and research institutes. Depending on the profile of the organization one is involved with, the area of functioning varies. So it is worth having a go at it.

##### Course Features

**24X7 Access:**You can view lectures as per your own convenience.**Online lectures:**22 hours of online lectures with high-quality videos.**Updated Quality content:**Content is latest and gets updated regularly to meet the current industry demands.

##### Test & Evaluation

Each lecture will have a quiz containing a set of multiple choice questions. Apart from that, there will be a final test based on multiple choice questions.

Your evaluation will include the overall scores achieved in each lecture quiz and the final test.

##### Certification

Certification requires you to complete all the lectures, quizzes, and the final test. Your certificate will be generated online after successful completion of course.

##### Topics to be covered

**Introduction**- Why do we need to study cryptography?
- What is the communication game?
- What is the protocols concept and what are the properties of function f(x)-1 and f(x-2)?
- What is the assumed protocol?
- What is the problem arising with the new concept?
- What is coin flipping over the telephone?
- Can we look at security analysis and an example?
- How can we get the function f(x)?
- How can we calculate the success probability?
- What is a planning strategy?
- What is the probability of cheating case 1 and 2?
- How can we calculate success probability experimentally?
- What is the magic function?

**Overview of Modern Cryptography**- What are the three goals of modern cryptography?
- What are the confidentiality, integrity, availability and mechanism?
- What are cryptographic attacks?
- What is the objective of cryptanalysis?
- What is the non-cryptanalytic attack and confidentiality threat?
- What are the threat to integrity 1, 2 and 3 and the threat of availability?
- What are active and passive attacks?
- What are the security services?
- What is the security mechanism?
- What are the digital signature and authentication and more on security mechanism?
- What is the relationship between service and mechanism?
- What are cryptographic algorithms and what are steganography / modern techniques?

**Introduction to Number Theory**- What are congruences and their properties?
- What are equivalence and residue class of modulo m and examples of class 1 class and 2?
- What is the theorem on equivalence and residue?
- Can we look at an example on the given theorem?
- What are the field theory (semigroups) and field theory (implication)?
- What is monoid and example on neutral elements?
- What are the residue class ring and unit group?
- What are zero divisors?
- What are Field and Euler's Totient Function and properties of Φ and an important result?
- What is Fermat's Little Theorem?

**Probability and Information Theory**- What is the importance of Probability and cipher uncertainty?
- What are Semantic Security and the notions of security and computational security?
- What are probability definitions (statistical and classical)?
- What is the probability distribution of random variables and what is Uniform and Binomial distribution?
- Law of large numbers 1.
- What is the law of large numbers 2?
- What are the Birthday paradox problem, actual problem and computing problem 1 and 2?
- What is an application of the paradox problem?
- What is Floyd's cycle-finding algorithm?
- How can we measure information and entropy?

**Classical Cryptosystems**- Definitions behind cipher designs 1 and 2.
- What is Kerchoffs Principle and what is Cryptographic Communication?
- What are Classical Cryptography and simple substitution?
- What are the properties required for encryption and what is substitution cipher?
- What are the affine cipher and its inverse?
- What are the generalized affine cipher and an example of it?
- What are some Important Results 1 and 2?
- What are monoalphabetic, polyalphabetic and vigenere ciphers?
- What are hill ciphers and permutation ciphers?

**Cryptanalysis of Classical Ciphers**- What are Kerckhoff's principle and the models of cryptanalysis 1 and 2?
- What is the statistical analysis?
- What is cryptanalysis of a monoalphabetic, affine and vigenere cipher?
- What is the Kasiski test?
- What is an index of coincidence 1?
- What is an index of coincidence 2?
- What is the mutual index of coincidence?
- What is computing mutual index?
- Can we look at two examples of vignere cipher?
- What is cryptoanalysis of hill cipher?

**Shannons Theory**- What are Shannon's theory and unconditional security?
- What are a prior and a posteriori probabilities?
- What is perfect secrecy 1 and 2?
- What are an example on perfect secrecy 1 and 2 and generalization of example?
- Can we look at an example on shift cipher with perfect secrecy and its mathematical formulation?
- What is the theorem on perfect secrecy?
- What are cryptographic properties 1 and 2?

**Shannons Theory (Contd...1)**- What is the one-time pad, unconditionally secured scheme and practical problems?
- Can we revisit entropy?
- What is Huffman encoding with an example?
- Can we look at more results on entropy?
- What is the proof of the theorem 1 and 2?
- Can we compare perfect cipher with ideal cipher?
- What is unicity, brute force attack, spurious keys, an entropy of plain text and redundancy?

**Shannons Theory (Contd...2)**- What is protection against brute force?
- What are spurious keys, second-order approximation and redundancy?
- What is the lower bound of equivocation of the key?
- What are the possible keys?
- What is the lower bound of the spurious key?
- What is unicity distance and unicity distance for substitution ciphers?
- Can we look at an example on endomorphic cipher?
- What is the proof of commutative ciphers?
- What are idempotent ciphers and what are the conclusions drawn?
- What is the concept of rounds?

**Symmetric Key Ciphers**- What is symmetric key setting and types of symmetric key ciphers?
- What are full-size key ciphers?
- What are permutation ciphers and partial-size key ciphers 1 and 2?
- What are the components of modern block ciphers?
- What are diffusion (P) boxes, S box and other components?
- What are the properties of EXOR?
- What is the diffusion and confusion data flow diagram?
- What are the practical ciphers (Feistel cipher)?
- What is Feistel permutation?

**Block Cipher Standards (DES)**- What are data encryption standards and DES numerology?
- What are initial permutations and DES expansion table?
- What is S box table with decimal values and what are the properties of S box?
- What is DES subkey?
- Some important points about DES and an exercise.
- What are the weak keys?
- What is sample round key generation and multiple DES?
- What is meet in the middle attack and security of 2DES?

**Block Cipher Standards (AES)**- What are the finite fields and complex fields?
- What is a polynomial over a field?
- What are the operations on a polynomial?
- Can we look at an addition example?
- What is multiplication operation, irreducible polynomial and an example of multiplication?
- What is the concept of a generator( Fernets Little theorem)?
- What is the proof of the theorem?
- What is the AES and Rijndael algorithm?
- What is the difference between Rijndael and AES?
- What are the AES Sbox and AES Sbox Affine mapping?
- What are the mix columns?

**Block Cipher Standards (AES) (Contd.)**- What is the AES key schedule?
- What is the key expansion?
- What is the key scheduling algorithm?
- What is the round constant?
- when nk>6 and an example on different key sizes
- What is the algorithm of encryption process?
- What is the inverse cipher (description)?
- What is the algorithm of the decryption process?
- How can we push a linear transformation using an XOR, steps for a two-round variant and implementation on modern processors?
- How can we make AES computation fast, some further reading and an exercise?
- What happens when the number of rounds of cipher is fixed?

**Linear Cryptanalysis**- What is the cipher transformation?
- What is the definition and algorithm of SPN ciphers?
- Can we look at an example of Gpig cipher and modification of SPN structure and key scheduling of the cipher?
- What is the linear cryptanalysis?
- What is piling up Lemma and generalized Lemma?
- What is the linear approximation of the S box and S box in terms of random variables?
- What is representing the approximations?
- What is the linear approximation table?
- What is the linear attack explanation 1 and 2 and what is the attack?

**Differential Cryptanalysis**- What are the key points of Differential Cryptanalysis?
- Can we have a recap of Gpig example?
- What is the informal working of the attack and obtaining differential characteristics fo the S box?
- What is the delta set and an example set?
- What is a non-uniform output distribution of XOR's of an S box and difference distribution table and propagation ratio?
- What is the differential trail?
- Can we look at an example of the differential trail?
- How can we obtain differential for 3 rounds and a real attack?
- How can we have an immunity against DC, an exercise and further reading?

**Few other Cryptanalytic Techniques**- What are common cryptanalytic techniques and a cap of differential cryptanalysis?
- What is Boomerang attack?
- Can we look at an example of Boomerang attack?
- What is the M layer?
- Can we look at the differential analysis of Phi function 1?
- Can we look at the differential analysis of Phi function 2?
- How can we obtain full round characteristics and the actual attack?
- How can we find the k1 key and other keys?
- What are the square attack on 4 round AES and the invariance of the active attack?

**Overview of S-Box Design Principles**- What is S Box?
- What is a boolean function?
- Can we look at explanation to boolean functions and scalar product of sequences?
- What is non-linearity 1 and 2?
- Can we look at the compact representation of linear functions?
- What are the effect of input transformation and strict avalanche criteria?
- strict avalanche criteria?
- What is boolean function satisfying SAC?
- Can we look at an example of a boolean function satisfying SAC?
- What are Bent function and its example?
- How can we create a balanced non-linear function?

**Modes of Operation of Block Ciphers**- What is the need for modes of block ciphers and what is electronic code book?
- What are the properties of modes?
- How can the ciphertext be stolen 1?
- How can the ciphertext be stolen 2?
- What is cipher block chaining?
- What are IV based attacks?
- What is error propagation in the case of CBC, its disadvantages and certain points?
- What is the output feedback mode and counter mode?
- How do modern-day modes function and what are tweakable modes?
- What is a watermark attack?

**Stream Ciphers**- Can we compare block with stream ciphers and what is the one-time pad?
- What are synchronous stream ciphers?
- What are the properties of synchronous stream ciphers and its model?
- What are self-synchronization stream ciphers and their properties?
- What is feedback shift register and linear feedback shift register?
- Can we look at an example of LFSR and periodicity of its sequences?
- How can we reconstruct the LFSR (an example)?

**Stream Ciphers (Contd...1)**- Some basic concepts related to Stream Ciphers and what is the LFSR structure?
- How can we generate a sequence and theorem of LFSR?
- What is the proof for the theorem 1 and 2?
- What is linear complexity and considering another lemma?
- What is Berlekamp Masseys algorithm?
- What is the discrepancy and how can it be corrected?
- How can we prove the induction hypothesis?
- What is the recursive construction of polynomial?
- Can we look at an example?

**Stream Ciphers (Contd...2)**- What are non-linear feedback shift registers?
- What are de Bruijn sequence and an example of de Bruijn generator?
- How can we convert LFSR to a de Bruijn FSR and what are stream ciphers based on LFSR?
- What are non-linear combination generator and an example using Geffe generator?
- What are the correlation attacks?
- What is correlation immunity?
- What is the summation generator, clock controlled generator and shrinking generator and what are modern stream ciphers?

**Pseudorandomness**- What is the usefulness of Pseudorandomness in cryptography and what is random bit generator?
- What are a pseudorandom bit generator and random tests?
- What are the polynomial statistical test and next bit test and the universality of the next bit test?
- What are random bit test and de-skewing?
- What is FIPS pseudo-random bit generator?
- What are the five basic tests?
- What is the normal distribution and chi-square distribution?
- What is hypothesis testing?
- What is the RSA bit PRBG and Blum Blum Shub Generator?

**Cryptographic Hash Functions**- What is data integrity, applications of the hash function and what is a keyed hash function?
- What is a definition of cryptographic hash function and how do we define a preimage problem?
- What are the collision problem and the random oracle model?
- What is an example of the non-ideal hash function?
- What is independence theorem and what is the algorithm in the random oracle model?
- What is the algorithm of find-preimage and find the second preimage?
- What is algorithm find collision and comparison of security criteria?
- What is the first reduction?
- What is the second reduction?

**Cryptographic Hash Functions (Contd...1)**- What is the proof on the assumption 1?
- What is the proof on the assumption 2?
- Can we look at the construction of iterated hash function?
- What are optimal output construction and a typical preprocessing step?
- What is Merkel damaged construction?
- What is the algorithm?
- What is the proof of collision resistance?
- What is the proof of collision resistance (assuming different cases)?
- Can we conclude considering the t=1 case?
- What are the different theorems applicable?

**Cryptographic Hash Functions (Contd...2)**- What is the iterated hash function and ideal hash function?
- What are the commitment scheme and its pitfalls?
- Can we look at MAC construction example?
- What is the attack and how can we forge MAC?
- What is Joux's attack?
- What are multi collisions 1 and 2?
- What is the multi-collision attack and can we look at a demo on meaningful collisions?
- What is the problem with meaningful collisions and weaker collisions?

**Cryptography and Network Security - Final Quiz**