P16 A natural question is whether we can use a nonce and pu.pdf
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The document proposes a protocol for end-point authentication using nonces and public key cryptography involving Alice and Bob. It outlines the steps of the communication process and raises a question about potential vulnerabilities, specifically how an adversary, Trudy, could execute a man-in-the-middle attack. It also requests a diagram of the protocol and an explanation of the attack method without using certificates.
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P16 A natural question is whether we can use a nonce and pu.pdf
- 1. P16. A natural question is whether we can use a nonce and public key cryptography to solve the end-point authentication problem in Section 8.4 . Consider the following natural protocol: (1) Alice sends the message "I am Alice" to Bob. (2) Bob chooses a nonce, R, and sends it to Alice. (3) Alice uses her private key to encrypt the nonce and sends the resulting value to Bob. (4) Bob applies Alice's public key to the received message. Thus, Bob computes R and authenticates Alice. a. Diagram this protocol, using the notation for public and private keys employed in the textbook. b. Suppose that certificates are not used. Describe how Trudy can become a "woman- inthe-middle" by intercepting Alice's messages and then pretending to be Alice to Bob.