System and Network Security Introduction
This test has the concepts related to cryptography and network security. This test is useful for CS, GATE and other aspirants.
Questions
Which of the following is incorrect about X.509 Authentication Service?
- It is used to construct a public key certificate.
- It also defines authentication protocols.
- In this service, the algorithms are not standardised, but RSA recommended.
- It uses public-key crypto and digital signatures.
- It handles double encryption, non-standard mode of use, session keys, password attacks.
Which of the following information is not issued by a Certification Authority (CA) for X.509 Certificates?
- Signature algorithm identifier
- Issuer X.500 name (CA)
- Subject public-key info (algorithm, parameters, key)
- Period of validity (from - to dates)
- User's keys
Which of the following is the incorrect statement about the Authentication Server (AS) in Kerberos 4?
- It provides the authentication to the Ticket Granting Server(TGS).
- It verifies the user's access rights in the database.
- It creates the session key for the database.
- It encrypts the user's keys from user's password.
- It also decrypts ticket and verifies the request.
Which of the following is incorrect about Block ciphers in cryptography?
- These ciphers process messages in blocks.
- These ciphers process messages a bit or byte at a time.
- Many current ciphers are block ciphers.
- These ciphers use bits, that have to be available before the block can be processed.
- These are used in broader range of applications.
Which assumption is not considered in Key Distribution techniques in cryptography?
- This approach requires to have a shared key for the sender and the receiver.
- Exchange of keys also possible.
- It allows the data, without allowing others to see the key.
- The secure system can be failure in this technique.
- It also works for asymmetric schemas.
Identify the incorrect statement about Data Encryption Standard (DES) algorithm?
- It uses 56 bit key to encrypt the data.
- It uses the block cipher scheme.
- DES depends on the key size and nature of algorithm both.
- With a key length of 56 bits, there are 2^56 possible keys.
- DES partitions input block into thee parts.
Which of the following is incorrect about Differential Cryptanalysis attack on DES algorithm?
- It uses multiple text blocks.
- It performs attack by repeatedly encrypting plaintext pairs with known input XOR.
- This technique is not efficient for large number of rounds.
- It gives linear equation for key bits.
- The differential cryptanalysis attack is complex and provides a complete description.
Which of the following functionality does S/MIME (Secure/Multipurpose Internet Mail Extensions) algorithm not contain?
- It is used for content types and texts messages.
- S/MIME supports in many mail agents.
- It has signed data to encode messages.
- It has encrypted content and associated keys.
- It uses digital signatures with DES algorithm.
Which of the following is incorrect about S/MIME Certificate Processing?
- It uses X.509 v3 certificates.
- Each client has a list of trusted CA’s certificates.
- Each client has own public/private key pairs and certificates.
- The certificates must be signed by trusted CA’s.
- It verifies the incoming signatures and decrypt outgoing messages.
Which of the following assumption is not included in Pretty Good Privacy (PGP) algorithm?
- It is used for email security.
- It can be used for file storage applications.
- It does not use digital signature service.
- It uses RSA algorithm to authenticate the message.
- It runs on a wide range of systems, in both free and commercial versions.
Which of the following is the incorrect statement about Double-DES?
- It uses 2 DES for encryption.
- Decryption requires that the keys be applied in reverse order.
- It results in a dramatic increase in cryptographic strength for DES.
- It uses 2 keys for processing.
- It is used to provide the potential vulnerability of DES to a brute force attack.
Which of the following is the incorrect statement about Electronic Codebook Book (ECB)?
- The messages have separate blocks for encryption.
- Each block is encoded independently of the other blocks.
- Encryption/decryption using the same key.
- Plaintext uses 64 bit blocks.
- Each previous cipher blocks is chained with current plaintext block.
Which of the following is false about Replay Attacks in network security?
- It occurs where a valid signed message is copied and later resent.
- The message repetition that can be logged.
- The message repetition that cannot be detected.
- It used sequence numbers for the process.
- There is no timestamp defined in this attack.
Which of the following is not a Digital Signature Property?
- It must depend on the message signed.
- It must be practically save digital signature in storage.
- Security depends on sender’s private-key.
- The signed message and signature should be encrypted.
- The message can encrypt using receivers private-key.
Which of the following is false about Symmetric Encryption Approach in cryptography?
- It uses a trusted Key Distribution Center (KDC).
- Each party shares own master key with KDC.
- There is a session keys is maintained between the parties.
- The master keys are used to distribute the session keys to both the parties.
- This approach is useful for more then two senders.