It seems there are contradicting answers for this question here on Chegg. Some s
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It seems there are contradicting answers for this question here on Chegg. Some say that using the personalized secret key denies the ability for someone to impersonate another person, while others say the opposite is true. Which is right, and why? Thanks in advance!!
Q.1 Suppose Alice, Bob, and Carol want to use secret key technology to authenticate each other. If they all used the same secret key K, the Bob could impersonate Carol to Alice (actually any of the three can impersonate the other to the third). Suppose instead that each had their own secret key, so Alice uses KA, Bob uses KB and Carol Uses Kc. This means that each one to prove his or her identity responds to a challenge with a function of his or her secrer key and the challenge ls this mone secure than hang them all use the same secret key K?Explanation / Answer
Neither of them have anything that is truly unique to them which they can use to authenticate themselves and ensure that their identity won't be forged. In the first case, if they all have same secret key K, anyone could impersonate anyone else. Without the use of public key technology, they will still need to know each other's keys for the verification, which means they can still forge each other's messages. So, the second method is also not secure unless they have a public key.
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