Course Title: Network Security and Cryptography
Course Code: PEC-CSE-411-G
Semester: B.Tech. 7th Semester (CSE)
February—2022 Examination
Short Answer Questions (6 × 2.5 = 15 marks)
- (a) E-mail Security
(b) Reinforce technique with example
(c) Security Handshake pitfalls
(d) Feistel Cipher
(e) Avalanche effect
(f) Role of session key in public key schemes
UNIT - I (15 marks)
- (a) Four substitution techniques – merits/demerits. [10]
(b) Transposition techniques. [5] - (a) Design principles of block cipher. [8]
(b) Fermat and Euler's theorem. [7]
UNIT - II (15 marks)
- (a) RSA encryption/decryption (p = 3, q = 11, e = 7, N = 5). [7]
(b) Strengths and weaknesses of DES. [8] - (a) Subkey and S-box generation in Blowfish. [8]
(b) Digital Signature in detail. [7]
UNIT - III (15 marks)
- (a) Secure Socket Layer (SSL) and steps in protocol. [7]
(b) Architecture of IP Security. [8] - (a) Electronic Money – usefulness. [7]
(b) Secure Electronic Transaction with diagram. [8]
UNIT - IV (15 marks)
- (a) Kerberos – authenticated service. [8]
(b) Honey pots and KDC. [7] - (a) Certificate based authentication. [8]
(b) Security handshake pitfalls. [7]
December—2022 Examination
Short Answer Questions (6 × 2.5 = 15 marks)
- (a) Product cipher
(b) Homophonic Substitution Cipher
(c) Cipher Block Chaining
(d) DES Design Principles
(e) Email Security
(f) Kerberos
UNIT - I (15 marks)
- (a) Elements of cryptographic operation with diagram. [10]
(b) Polyalphabetic Substitution Cipher. [5] - (a) Transposition techniques with examples. [8]
(b) Problem of key distribution in symmetric cryptography. [7]
UNIT - II (15 marks)
- (a) Overview of DES Encryption Algorithm with diagram. [7.5]
(b) Limitations of DES modes. [7.5] - Subkey generation in Blowfish. [15]
UNIT - III (15 marks)
- (a) Why SSL is between application and transport layer. [7.5]
(b) Purpose of SSL alert protocol. [7.5] - (a) Significance of time stamping protocol. [8]
(b) How SET protects payment info from merchant. [7]
UNIT - IV (15 marks)
- (a) Certificate based authentication. [8]
(b) Biometric based authentication. [7] - Single Sign-On (SSO) approach in detail. [15]
May—2023 Examination
Short Answer Questions (6 × 2.5 = 15 marks)
- (a) Cryptanalysis
(b) Rail-Fence Technique
(c) Electronic Codebook
(d) DES Weak Keys
(e) Electronic Money
(f) Biometric Authentication
UNIT - I (15 marks)
- (a) Substitution techniques with examples. [10]
(b) Two ways to modify plain text to cipher text. [5] - (a) Encryption and Decryption with examples. [8]
(b) Diffie–Hellman Key Exchange Algorithm. [7]
UNIT - II (15 marks)
- (a) One-time initialization and round steps in AES. [7.5]
(b) Advantages and disadvantages of DES modes. [7.5] - Subkey generation in Blowfish. [15]
UNIT - III (15 marks)
- (a) SSL handshake protocol. [7.5]
(b) Difference between SHTTP and SSL. [7.5] - (a) Steps in SET. [8]
(b) Difference between 3-D Secure and SET. [7]
UNIT - IV (15 marks)
- (a) Problems and solutions of Smart Card Technology. [8]
(b) Kerberos and internet security. [7] - (a) Key Distribution Center (KDC). [7.5]
(b) Security handshake pitfalls. [7.5]
November—2023 Examination
Short Answer Questions
- (i) Cipher Text
(ii) Drawbacks of symmetric cryptography
(iii) E-mail Security
(iv) Single Sign-On approach
(v) CIA triad
UNIT - I (15 marks)
- Explain the basic concepts of encryption and decryption techniques with suitable examples.
- Describe substitution ciphers. How is their working different from transposition ciphers?
UNIT - II (15 marks)
- What do you mean by digital signatures? How do they act as a medium of trust between communicating parties?
- (a) Differentiate between symmetric and asymmetric encryption approaches.
(b) Explain the RSA algorithm.
UNIT - III (15 marks)
- What is SSL? Detail the events required for a successful SET transaction.
- Explain the Secure HTTP (S-HTTP) protocol along with its advantages and disadvantages. Why is Secure HTTP preferred over HTTP? Also discuss the vital features of TSP.
UNIT - IV (15 marks)
- Describe in detail the Kerberos authentication service. Also highlight its chief drawbacks.
- (a) Security handshake pitfalls.
(b) Key Distribution Center (KDC).
Dec-2024 Examination
Short Answer Questions (8 × 2.5 = 20 marks)
- (i) Define plain-text and cipher-text. How are they related in encryption?
(ii) What is the difference between substitution and transposition techniques in cryptography?
(iii) What is the primary purpose of the RSA algorithm in encryption?
(iv) How are digital signatures used in cryptographic communication?
(v) What is the main function of Secure Socket Layer (SSL) in internet security?
(vi) How does Transport Layer Security (TLS) enhance the security of data transmissions?
(vii) Define Single Sign-On (SSO). How is it used in enterprise systems?
(viii) What are authentication tokens and how are they used in secure systems?
UNIT - I (15 marks)
- Describe the process of symmetric key cryptography and explain the role of encryption and decryption keys in the process. [15]
- Discuss the challenges and benefits of asymmetric key cryptography over symmetric key cryptography. Provide real-world examples to illustrate their usage. [15]
UNIT - II (15 marks)
- Explain the Data Encryption Standard (DES) algorithm in detail. [15]
- Describe the Advanced Encryption Standard (AES) and its operation along with its structure. [15]
UNIT - III (15 marks)
- Explain the concept of Secure Electronic Transactions (SET) and compare it with SSL. [15]
- Discuss the concept of electronic money. How do security protocols like SSL and SET play a role in safeguarding digital transactions? [15]
UNIT - IV (15 marks)
- Describe the Single Sign-On (SSO) approach and its advantages in enterprise security. What are some common pitfalls in its implementation? [15]
- Compare and contrast Certificate-based Authentication with Token-based Authentication. What are the use cases for each method? [15]