12. (10 points) Considering the following key-establishment protocol, designed to let Alice and Bob decide on a shared p

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12 10 Points Considering The Following Key Establishment Protocol Designed To Let Alice And Bob Decide On A Shared P 1 (85.67 KiB) Viewed 66 times

12. (10 points) Considering the following key-establishment protocol, designed to let Alice and Bob decide on a shared private key: 1. Alice chooses k, ra ← {0,1}" at random, and sends s := k ☺ ra to Bob. 2. Bob chooses rå ← {0, 1}” at random and sends t := s ⇒ rŋ to Alice. and sends u to Bob. 3. Alice computes u := : tra 4. Finally, Alice outputs k and Bob computes u ⇒ r. Show that Alice and Bob output the same key. Decide whether the protocol is secure and justify your answer.