3. Digital Signature and Hash Function (14 Points] Recall that we use both a public key system and a hash function when computing digital signatures. Use the following notation for clarity: Message = M; Message M signed by A = [M]a; Message M encrypted with A's public key = {M}A, Hash of Message M=h(M). a. [2 Points] Precisely how is a digital signature computed and verified? b. [2 Points] Suppose that the public key system used to compute and verify signatures is insecure, but the hash function is secure. Show that you can forge signatures. c. [2 Points] Suppose that the hash function used to compute and verify signatures is insecure, but the public key system is secure. Show that you can forge signatures. d. [2 Points] Show that a digital signature provides integrity protection. e. [2 Points) Show that a digital signature provides non-repudiation. f. [2 Points] Suppose that Alice wants to sign the message M and send the result to Bob. In terms of our standard notation, what does Alice compute? g. [2 Points] What does Alice send to Bob and how does Bob verify the signature? 3. Digital Signature and Hash Function (14 Points] Recall that we use both a public key system and a hash function when computing digital signatures. Use the following notation for clarity: Message = M; Message M signed by A = [M]a; Message M encrypted with A's public key = {M}A, Hash of Message M=h(M). a. [2 Points] Precisely how is a digital signature computed and verified? b. [2 Points] Suppose that the public key system used to compute and verify signatures is insecure, but the hash function is secure. Show that you can forge signatures. c. [2 Points] Suppose that the hash function used to compute and verify signatures is insecure, but the public key system is secure. Show that you can forge signatures. d. [2 Points] Show that a digital signature provides integrity protection. e. [2 Points) Show that a digital signature provides non-repudiation. f. [2 Points] Suppose that Alice wants to sign the message M and send the result to Bob. In terms of our standard notation, what does Alice compute? g. [2 Points] What does Alice send to Bob and how does Bob verify the signature