JNTU
JNTU B.Tech IV Year INFORMATION SECURITY Previous Question Paper (February/March - 2022 - R18)
Answer any five questions. All questions carry equal marks.
Main
With the help of a neat diagram, explain the model for network security.
Answer
The network security model consists of four essential components designed to protect information during transmission: an information channel, a message source, a message destination, and a security transformation mechanism. The source transmits a message to the destination via a channel, but to ensure security, a transformation is applied to the message using a secret key. A trusted third party, such as a security service provider or a key distribution center, is often involved to manage the distribution of keys and ensure the integrity of the communication.
The process involves:
- Message Source: The entity that generates the information to be sent.
- Security Transformation: The process of encrypting the message using a cryptographic algorithm and a secret key to render it unintelligible to unauthorized parties.
- Information Channel: The transmission medium (e.g., internet, fiber optics) that connects the source and destination.
- Trusted Third Party: An entity that facilitates the secure exchange of keys or provides security services like authentication and digital signatures.
- Message Destination: The intended recipient who possesses the corresponding key to decrypt and recover the original information.
Make comparisons between the symmetric cipher model, substitution ciphers, and transposition ciphers.
Answer
| Feature | Symmetric Cipher Model | Substitution Cipher | Transposition Cipher |
|---|---|---|---|
| Mechanism | Uses a shared secret key for both encryption and decryption. | Replaces each plaintext character/block with another character/block. | Rearranges the positions of the plaintext characters without changing them. |
| Complexity | High; relies on complex mathematical algorithms (e.g., AES, DES). | Low to moderate; relies on mapping tables or shifts (e.g., Caesar, Vigenère). | Moderate; relies on permutations or geometric patterns (e.g., Rail Fence). |
| Frequency Analysis | Resistant if the algorithm is strong and the key space is large. | Vulnerable to frequency analysis unless polyalphabetic. | Vulnerable to frequency analysis as character frequencies remain unchanged. |
| Primary Goal | Provide robust confidentiality via computational hardness. | Obscure the message content by changing symbols. | Obscure the message content by changing the order of symbols. |
For each of the following assets, assign a low, moderate, or high impact level for the loss of confidentiality, availability, and integrity respectively. Justify your answers.
Financial Organization managing routine administrative information.
Answer
Sign in to view the complete answer paper.
Organization managing public information on its web server.
Answer
Sign in to view the complete answer paper.
Law enforcement organizations managing extremely sensitive investigative information.
Answer
Sign in to view the complete answer paper.
In RSA, Given n=12091 and e=13, encrypt the message “THIS IS TOUGH” using the 00 to 26 encoding scheme. Decrypt the ciphertext to find the original message.
Answer
Sign in to view the complete answer paper.
Describe the steps in finding the message digest using the SHA-512 algorithm. What is the order of finding two messages having the same message digest?
Answer
Sign in to view the complete answer paper.
Explain HMAC.
Answer
Sign in to view the complete answer paper.
Discuss about authentication requirement.
Answer
Sign in to view the complete answer paper.
Assume client C wants to communicate with a server S using Kerberos protocol. How can it be achieved?
Answer
Sign in to view the complete answer paper.
Why does PGP compress the message? What are the reasons for compressing the signature before encryption?
Answer
Sign in to view the complete answer paper.
Explain the X.509 certificate formats. Why Kerberos is needed? What is one-way authentication?
Answer
Sign in to view the complete answer paper.
Discuss the IP security architecture and also explain basic combinations of security associations with a neat diagram.
Answer
Sign in to view the complete answer paper.
Define Firewall. Explain its characteristics, types, services, and limitations.
Answer
Sign in to view the complete answer paper.