Oib Part3
- 1.A form of active wiretapping attack in which the attacker intercepts and selectively modifies communicated data in order to masquerade as one or more of the entities involved in a communication
- A.
Man-in-the-middle attack
- B.
A) Mandatory access control b) Intrusion detection system c) Meet-in-the-middle attack d) None of the statements a) Mandatory access control b) Intrusion detection system c) Meet-in-the-middle attack d) None of the statements Mandatory access control
- C.
Intrusion detection system
- D.
Meet-in-the-middle attack
- E.
None of the statements
- 2.To figure out the password by trying possible likely passwords from a list is called
- A.
Password attack
- B.
Brute force attack
- C.
Word list attack
- D.
Dictionary attack
- E.
Keystroke attack
- 3.To figure out the password by trying every possible keystroke combination is called
- A.
Password attack
- B.
Word list attack
- C.
Keystroke attack
- D.
Dictionary attack
- E.
Brute force attack
- 4.Suppose that your plaintext is 228 bytes long and you are using RC4, how many bytes are needed for padding
- A.
RC4 does not need padding
- B.
Depends on the size of the block
- C.
4
- D.
8
- E.
6
- 5.The algorithm developed by Feistel at IBM in the early 1970s and later adopted as a U.S. Federal Information Processing Standard for encrypting unclassified information is known as
- A.
Digital Cipher Standard
- B.
Digital Encryption Standard
- C.
Data Encryption Standard
- D.
Digital Cryptography Standard
- E.
Data Cryptography Standard
- 6.Indicate the definition for Revocation
- A.
Providing an entity with the legal right to use or transfer a resource to others
- B.
Concealing the identity of an entity involved in some process
- C.
Acknowledgement that services have been provided
- D.
Retraction of certification or authorisation
- E.
Preventing the denial of previous commitments or actions
- 7.Encrypt the message MUSTSE with the key "largest" using the Playfair cipher
- 8.In Feistel Cipher an iterated cipher with an internal function called a ___________ functio
- A.
Floor
- B.
Scheme
- C.
Round
- D.
Ceil
- E.
Iteration
- 9.Indicate the definition for Witnessing
- A.
Providing an entity with the legal right to use or transfer a resource to others
- B.
Verifying the creation or existence of information by an entity other than the creator
- C.
Acknowledgement that services have been provided
- D.
Acknowledgement that information has been received
- E.
Concealing the identity of an entity involved in some process
- 10.The word “asymmetric” in public-key cryptography means
- A.
The key to encrypt is different from the key to decrypt
- B.
The key to encrypt is the same with the key to decrypt
- C.
The algorithm to encrypt is the same with the algorithm to decrypt
- D.
None of the listed answers
- E.
The algorithm to encrypt is different from the algorithm to decrypt
- 11.In cryptography, the original message before encryption is called
- A.
Plaintext
- B.
Ciphertext
- C.
Cleartext
- D.
Originaltext
- E.
Messagetext
- 12.A general cipher design principle, not a specific cipher used by most block ciphers
- A.
AES
- B.
RC4
- C.
DES
- D.
Feistel Cipher
- E.
A5/1
- 13.Indicate the definition for Non-repudiation
- A.
Retraction of certification or authorisation
- B.
Concealing the identity of an entity involved in some process
- C.
Preventing the denial of previous commitments or actions
- D.
Providing an entity with the legal right to use or transfer a resource to others
- E.
Acknowledgement that services have been provided
- 14.How many possible keys does the Playfair cipher have? Ignore the fact that some keys might produce identical encryption results
- A.
25
- B.
26
- C.
26!
- D.
625
- E.
25!
- 15.Why is it that the one-time pad can only be used once
- A.
All of the statements
- B.
If two messages encrypted with the same “one-time” pad key the probability of leaking the key is high
- C.
If two messages encrypted with the same “one-time” pad key and when two different ciphertexts XORed with each other the key disappears
- D.
If two messages encrypted with the same “one-time” pad key and when two different ciphertexts XORed with each other the plaintext disappears
- E.
Two messages encrypted with the same “one-time” pad key the produced ciphertext always will be the same
- 16.Set of tools for generating new viruses automatically is known as a( n ) _____________
- A.
Exploits
- B.
Flooders
- C.
Kit (virus generator)
- D.
Auto-rooter
- E.
Downloaders
- 17.Which of the followings are drawbacks of OTP
- A.
OTP is highly secure algorithm
- B.
Pad must be securely transmitted to the recipient before the ciphertext can be decrypted.
- C.
A pad (key) consisting of a randomly selected string of bits that is the same length as the message.
- D.
The pad (key) is the same length as the message
- E.
Or modern high data-rate systems, a one-time pad cipher is totally impractical
- 18.Which malicious program Captures keystrokes on a compromised system
- A.
Zombie
- B.
Trojan horse
- C.
Spammer
- D.
Keylogger
- E.
Rootkit
- 19.Code specific to a single vulnerability or set of vulnerabilities is known as a( n ) _____________
- A.
Kit (virus generator)
- B.
Exploits
- C.
Downloaders
- D.
Flooders
- E.
Auto-rooter
- 20.Which software prevents Trojan horses from entering the system through back door
- A.
Virus
- B.
Trapdoor
- C.
Firewall
- D.
Cache
- E.
Worm
- 21.A secret data value, usually a character string, that is used as authentication information
- A.
Plaintext
- B.
Public key
- C.
Password
- D.
Secret key
- E.
Private key
- 22.Which of the following statement is NOT TRUE
- A.
Any password the brute force attack tries, the dictionary attack also tries
- B.
The dictionary attack tries fewer passwords than does the brute force attack
- C.
The dictionary attack is faster than the brute force attack
- D.
The brute-force attack tries many additional passwords that the dictionary attack does not
- E.
A hacker probably start with a dictionary attack and if that fails, move on to a modified brute force attack
- 23.Which of the following are examples of the host independent malicious programs
- A.
Trap door
- B.
Logic Bombs
- C.
Zombie
- D.
Worm
- E.
Trojan Horses
- 24.Which of the following statement is NOT TRUE regarding key recovery via threshold schemes
- A.
If one of the trustees leaves the company, the secret is still safe, and there’s no need to restart the key recovery process from the beginning
- B.
If one trustee leaves the company, his or her share becomes invalid
- C.
No one person can recover keys; it takes a group acting together
- D.
If one of the trustees is unavailable, it’s still possible to perform the operation
- E.
The threshold scheme has many advantages over other key recovery programs
- 25.Which of these is NOT a recommended guideline for a good password
- A.
Avoid using personal information
- B.
Avoid using actual words
- C.
Memorise it
- D.
Do not write it down
- E.
Store the password in a safe place
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