GATE 2016: Consider that BB wants to send a message mm that is digitally signed to AA. Let the pair of private and public keys for AA and BB be denoted by Kx−Kx− and Kx+Kx+ for x=A,Bx=A,B, respectively. Let Kx(m)Kx(m) represent the operation of encrypting mm with a key KxKx and H(m)H(m) represent the message digest. Which one of the following indicates the CORRECT way of sending the message mm along with the digital signature to A?
Correct answer: B.
1. B is sending a message to A
2. So B will send the message m
3. In addition to the message, B will send the digital signature generated using the message and his private key
4. To generate Digital signature, B will take the Hashcode of the message ie H(m) and then encrpt with his private key. ie. Kb-, hence the answer is message (m) and Kb-(Hashcode of m)