This section contains more frequently asked Internet Security MCQs in the various competitive exams.
PRACTICE IT NOW TO SHARPEN YOUR CONCEPT AND KNOWLEDGE
1. In public key encryption system if A encrypts a message using his private key and sends it to B
- if B knows it is from A he can decrypt it using A’s public key
- Even if B knows who sent the message it cannot be decrypted
- It cannot be decrypted at all as no one knows A’s private key
- A should send his public key with the message
A. if B knows it is from A he can decrypt it using A’s public key
2. Message can be sent more securely using DES by
- encrypting plain text by a different randomly selected key for each transmission
- encrypting plain text by a different random key for each message transmission and sending the key to the receiver using a public key system
- using an algorithm to implement DES instead of using hardware
- designing DES with high security and not publicizing algorithm used by it
B. encrypting plain text by a different random key for each message transmission and sending the key to the receiver using a public key system
3. DES and public key algorithm are combined (i) to speed up encrypted message transmission (ii)to ensure higher security by using different key for each transmission (iii) as a combination is always better than individual system (iv) as it is required in e-Commerce
- i and ii
- ii and iii
- iii and iv
- i and iv
A. i and ii
4. A digital signature is
- a bit string giving identity of a correspondent
- a unique identification of a sender
- an authentication of an electronic record by tying it uniquely to a key only a sender knows
- an encrypted signature of a sender
C. an authentication of an electronic record by tying it uniquely to a key only a sender knows
5. A digital signature is required (i) to tie an electronic message to the sender’s identity (ii)for non repudiation of communication by a sender (iii) to prove that a message was sent by the sender in a court of law (iv) in all e-mail transactions
- i and ii
- i, ii, iii
- i, ii, iii, iv
- ii, iii, iv
B. i, ii, iii
6. A hashing function for digital signature (i) must give a hashed message which is shorter than the original message (ii)must be hardware implementable (iii) two different messages should not give the same hashed message (iv) is not essential for implementing digital signature
- i and ii
- ii and iii
- i and iii
- iii and iv
C. i and iii
7. Hashed message is signed by a sender using
- his public key
- his private key
- receiver’s public key
- receiver’s private key
B. his private key
8. While sending a signed message, a sender
- sends message key using public key encryption using DES and hashed message using public key encryption
- sends message using public key encryption and hashed message using DES
- sends both message and hashed message using DES
- sends both message and hashed message using public key encryption
A. sends message key using public key encryption using DES and hashed message using public key encryption
9. The responsibility of a certification authority for digital signature is to authenticate the
- hash function used
- private keys of subscribers
- public keys of subscribers
- key used in DES
C. public keys of subscribers
10. Certification of Digital signature by an independent authority is needed because
- it is safe
- it gives confidence to a business
- the authority checks and assures customers that the public key indeed belongs to the business which claims its ownership
- private key claimed by a sender may not be actually his
C. the authority checks and assures customers that the public key indeed belongs to the business which claims its ownership
