What is the formula for pre-images of a given hash value, where data block length = b bits and hash code = n bits?

• A. 2b-n
• B. 2b+n
• C. 2b/n
• D. 2n/b

Which of the following is not a basic property for employing hash function in practical applications?

• A. Variable input size
• B. Fixed output size
• C. Efficiency
• D. Preimage resistant

Which of the following property of the hash function makes the hash function strong?

• A. Efficiency
• B. Preimage resistant
• C. Second preimage resistant
• D. Collision resistant

Brute force attack does not concentrate on bit length of the hash value.

• A. True
• B. False
• C.
• D.

What can it be called, if an attacker determines the private key of the user, after breaking the signature scheme?

• A. Universal forgery
• B. Total break
• C. Selective forgery
• D. Existential forgery

Which of the following is not a requirement of digital signatures?

• A. Easy to produce
• B. Easy to recognize
• C. Easy to verify
• D. Computationally feasible

Who will be the involving parties in the direct digital signature scheme?

• A. Source and destination
• B. Source and third party
• C. Destination and third party
• D. Source and destination and third party

Which of the following sentence is incorrect in case for digital signatures?

• A. Signature key is of signing and public key for verification
• B. Public key for verification and signature is for authentication
• C. Signature key is for verification and public key for signing
• D. Both signing and verification is done by public key

What is the advantage of digital signing a hash instead of signing the entire data in RSA?

• A. Time saving
• B. Security
• C. Time saving and computationally less expensive
• D. Secured and less time requires

Which of the following cannot be achieved by the digital signature in symmetric key encryption?

• A. Message authentication
• B. Data integrity
• C. Non-repudiation
• D. Security of the message