Oib Part1
- 1.What is the purpose of Passive Attack?
- A.
A)To counter security attacks, and they make use of one or more security mechanisms to provide the service.
- B.
B)To learn or make use of information from the system but does not affect system resources
- C.
C)To provide timeliness of authorisation to use or manipulate information or resources
- D.
D)To bind information to an entity
- E.
E)To alter system resources or affect their operation.
- 2.Choose the definition of Security mechanism?
- A.
A) A potential for violation of security, which exists when there is a circumstance, capability, action, or event that could breach security and cause harm.
- B.
B) Any action that compromises the security of information owned by an organization
- C.
C) All of the statement
- D.
D) A processing or communication service that enhances the security of the data processing systems and the information transfers of an organization.
- E.
E) A process that is designed to detect, prevent, or recover from a security attack.
- 3.Given that the Caesar’s cipher is used, find the plaintext from the ciphertext. ZKDW GRHV WKH IRA VDB.
- A.
What does the fox say.
- B.
Option 2
- 4.The conversion of plaintext or data into unintelligible form by means of a reversible translation, based on a translation table or algorithm
- A.
A) Deciphering
- B.
B) Decryption
- C.
C) All of the statement
- D.
D) Encryption
- E.
E) Enciphering
- 5.What is the functionality of a block-cipher?
- A.
A) processes the input elements continuously, producing output one element at a time, as it goes along
- B.
B) A procedure used during symmetric block encryption that makes an output block dependent not only on the current plaintext input block and key, but also on earlier input and/or output.
- C.
C) processes the input one block of elements at a time, producing an output block for each input block.
- D.
D) exploits the characteristics of the algorithm to attempt to deduce a specific plaintext or to deduce the key being used
- E.
E) verification the integrity of a message
- 6.A two-letter sequence is called ______________.
- A.
A) None of the statements
- B.
B) Letter
- C.
C) Twogram
- D.
D) Bigram
- E.
E) Digram
- 7.The translation of encrypted text or data into original text or data
- A.
A) Decryption
- B.
B) Enciphering
- C.
C) All of the statements
- D.
D) Deciphering
- E.
E) Encryption
- 8.Choose the definition of Security service?
- A.
A) All of the statements
- B.
B) A process that is designed to detect, prevent, or recover from a security attack.
- C.
C) A processing or communication service that enhances the security of the data processing systems and the information transfers of an organization.
- D.
D) A potential for violation of security, which exists when there is a circumstance, capability, action, or event that could breach security and cause harm.
- E.
E) Any action that compromises the security of information owned by an organization
- 9.What is a Masquerade?
- A.
A) Preventing or inhibiting the normal use or management of communications facilities
- B.
B) The passive capturing of a data unit and its subsequent retransmission to produce an unauthorized effect
- C.
C) One entity pretends to be a different entity
- D.
D) Restricting access to resources to privileged entities.
- E.
E) Altering some portion of a legitimate message, or that messages are delayed or reordered, to produce an unauthorized effect
- 10.The output of an encryption algorithm; the encrypted form of a message or data
- A.
A) Cipher
- B.
B) Encryption
- C.
C) Plaintext
- D.
D) Ciphertext
- E.
E) Decryption
- 11.In which of the four basic password techniques the system periodically runs its own password cracker to find guessable passwords and cancels any passwords that are guessed and notifies the user
- A.
A) User education
- B.
B) Reactive password checking
- C.
C) User-generated passwords
- D.
D) Computer-generated passwords
- E.
E) Proactive password checking
- 12.Indicate the drawbacks of reactive password checking technique
- A.
A) resource intensive
- B.
B) Others may not be good judges of what is a strong password.
- C.
C) users will not be able to remember them
- D.
D) any existing passwords remain vulnerable
- E.
E) many users will simply ignore the guidelines.
- 13.A legitimate user who accesses data, programs, or resources for which such access is not authorized, or who is authorized for such access but misuses his or her privileges
- A.
A) Masquerader
- B.
B) Crypto analyzer
- C.
C) Misfeasor
- D.
D) Clandestine user
- E.
E) Cryptologist
- 14.An individual who is not authorized to use the computer and who penetrates a system's access controls to exploit a legitimate user's account
- A.
A) Masquerader
- B.
B) Misfeasor
- C.
C) Cryptologist
- D.
D) Clandestine user
- E.
E) Crypto analyzer
- 15.An authentication mechanism that enables the creator of a message to attach a code that acts as a signature.
- A.
A) Hybrid Cryptosystem
- B.
B) Diffusion
- C.
C) Diffie-Hellman Algorithm
- D.
D) Digital signature
- E.
E) Man-in-the-middle attack
- 16.Which of these is a mixing algorithm?
- A.
A) AES
- B.
B) RC4
- C.
C) RSA
- D.
D) DES
- E.
E) SHA1
- 17.Indicate the one of the purposes of salt used in the Unix password scheme
- A.
A) It effectively increases the length of the password without requiring the user to remember two additional characters.
- B.
B) It prevents password from being corrupted by intruders.
- C.
C) It prevents the users from creating passwords.
- D.
D) It effectively decreases the length of the password without requiring the user to remember two additional characters.
- E.
E) It is used as a secret key for encryption password.
- 18.In which of the four basic password techniques users can be told the importance of using hard-to-guess passwords and can be provided with guidelines for selecting strong passwords
- A.
A) Computer-generated passwords
- B.
B) Reactive password checking
- C.
C) Proactive password checking
- D.
D) User education
- E.
E) User-generated passwords
- 19.Indicate the one of the purposes of salt used in the Unix password scheme
- A.
A) It effectively decreases the length of the password without requiring the user to remember two additional characters
- B.
B) It prevents the users from creating passwords.
- C.
C) It prevents password from being corrupted by intruders
- D.
D) It prevents duplicate passwords from being visible in the password file
- E.
E) It is used as a secret key for encryption password.
- 20.In which of the four basic password techniques a user is allowed to select his or her own password. At the time of selection, the system checks to see if the password is allowable and, if not, rejects it
- A.
A) User education
- B.
B) Proactive password checking
- C.
C) User-generated passwords
- D.
D) Reactive password checking
- E.
E) Computer-generated passwords
- 21.Which of these types of cipher is most suitable to encrypt verbal communication via mobile phone?
- A.
A) Stream
- B.
B) Asymmetric
- C.
C) Block
- D.
D) Classical
- E.
E) Public-key
- 22.If a wrong key is entered to decrypt a message, what will happen?
- A.
A) The cryptosystem will stop working
- B.
B) the output will be gibberish
- C.
C) There is an error message
- D.
D) Nothing will happen
- E.
E) The output will not be visible
- 23.Suppose that your plaintext is 130 bytes long and you are using DES, how many blocks will be formed for the whole encryption process?
- A.
A) 8
- B.
B) 17
- C.
C) 16
- D.
D) 0
- E.
E) 9
- 24.Suppose that your plaintext is 115 bytes long and you are using RC4, how many bytes are needed for padding?
- A.
A) 8
- B.
B) RC4 does not need padding
- C.
C) Depends on the size of the block
- D.
D) 2
- E.
E) 4
- 25.Which of these statements is TRUE?
- A.
A) In symmetric-key cryptography, the key that is used to encrypt data is the same key that is used to decrypt it
- B.
B) In cryptography, to protect the contents of your files, you install a lock (a decryption algorithm) on your door (the computer).
- C.
C) The term “key” comes from the fact that the password you choose works in the same way that a conventional key works
- D.
D) The encryption algorithm performs its steps using the key to alter the ciphertext and convert it to plaintext
- E.
E) The decryption algorithm performs its steps using the key to alter the plaintext and convert it to ciphertext
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