Suppose that Alice wants to initiate a message exchange (also called session) to instruct her bank, NetBank, to pay Bob N40. Alice shares a long-term secret, X, with NetBank (hereafter denoted as...
Suppose that Alice wants to initiate a message exchange (also called session) to instruct her bank, NetBank, to pay Bob N40. Alice shares a long-term secret, X, with NetBank (hereafter denoted as C). Alice starts the session by sending a service request, (A, C, n), to NetBank, 3. a. where A is Alice's identity, C is NetBank's identity, and n is a nonce. Assume that NetBank keeps a record of the nonces used by Alice for X. Answer the following questions. Write out NetBank's response message to this request. The response message should enable Alice to verify that the response is in i. deed from an entity who knows the secret x. In order to secure the communication, Alice and NetBank need to establish a secret K, which is only valid for this session. Propose a method by which Alice urely establish a secret session key with the use of their long ii. session key, and Netßank could securely establish a secret sesson key with the use of their ong term secret, X ii Now, Alice can send her payment instruction (Me"Pay Bob N40 from my account") securely to NetBank using the session key. Construct the message in such a way that Bob cannot replay it, and the secrecy of the message is protected iv. Could an adversary attack this protocol causing some financial loss to Alice? Justify your answer.
Suppose that Alice wants to initiate a message exchange (also called session) to instruct her bank, NetBank, to pay Bob N40. Alice shares a long-term secret, X, with NetBank (hereafter denoted as C). Alice starts the session by sending a service request, (A, C, n), to NetBank, 3. a. where A is Alice's identity, C is NetBank's identity, and n is a nonce. Assume that NetBank keeps a record of the nonces used by Alice for X. Answer the following questions. Write out NetBank's response message to this request. The response message should enable Alice to verify that the response is in i. deed from an entity who knows the secret x. In order to secure the communication, Alice and NetBank need to establish a secret K, which is only valid for this session. Propose a method by which Alice urely establish a secret session key with the use of their long ii. session key, and Netßank could securely establish a secret sesson key with the use of their ong term secret, X ii Now, Alice can send her payment instruction (Me"Pay Bob N40 from my account") securely to NetBank using the session key. Construct the message in such a way that Bob cannot replay it, and the secrecy of the message is protected iv. Could an adversary attack this protocol causing some financial loss to Alice? Justify your answer.