Question

Alice wants to sign and then send a confidential letter M to Bob. Which one of the following is sent by Alice to Bob. Let

Apk: Alice's public key
Apr: Alice's private key
Bpk: Bob's public key
Bpr: Bob's private key
E(M,K): Encryption the message M with the key K
D(M,K): Decryption the message M with the key
K H(M): Hash value of M

(Select all that apply.)

1. A->B: E(H(M,Apk))
2. A->B: E(H(M), Bpr)
3. A->B: E(E(M,Apk),Bpk)
4. A->B: E_Apk(E_Bpr(M))
5. A->B: ED(M,Apr), Bpk)
6. A->B: E(E(M,Apr), Bpk)
7. A->B: D(E(M,Apr), Bpk)
8. A->B: E(E(M, Apr), Bpr)
9. A->B: E(H(M),Bpk)

Answer 1

9

Step-by-step explanation:

First step includes with hashing of confidential message H(M) then Alice will encrypt the hashed message with bobs public key E(H(M),Bpk) as it is available openly to send message to Bob

so 9th option clearly defines the complete procedure.