1. Engineering
  2. Computer Science
  3. 1a for this question use the following definitions let m...

Question: 1a for this question use the following definitions let m...

Question details

1A.

For this question, use the following definitions.

  • Let m be a message
  • Let Ka+ be the public key for Alice, and Ka+(m) be the function expression which indicates the message, m, is encrypted using Alice's public key
  • Let Ka- be the private key for Alice, and Ka-(m) be the function expression which indicates the message, m, is encrypted using Alice's private key
  • Let Kb+ be the public key for Bob, and Kb+(m) be the function expression which indicates the message, m, is encrypted using Bob's public key
  • Let Kb- be the private key for Bob, and Kb-(m) be the function expression which indicates the message, m, is encrypted using Bob's private key
  • Let Ka+() be the inverse function of Ka-(), so Ka+(Ka-(m))=Ka-(Ka+(m))=m
  • Let Kb+() be the inverse function of Kb-(), so Kb+(Kb-(m))=Kb-(Kb+(m))=m
  • Let H() be a hash function

QUESTION: If Alice wants to send a message that only Bob can read, what message does she send?

Ka-(m)
Ka+(Kb-(m))
Kb+(Ka+(m), H(m))
Kb-(m)
Ka+(m)
Kb+(m)
Ka+(Kb+(m))

1B.

For this question, use the following definitions.

  1. Let m be a message
  2. Let Ka+ be the public key for Alice, and Ka+(m) be the function expression which indicates the message, m, is encrypted using Alice's public key
  3. Let Ka- be the private key for Alice, and Ka-(m) be the function expression which indicates the message, m, is encrypted using Alice's private key
  4. Let Kb+ be the public key for Bob, and Kb+(m) be the function expression which indicates the message, m, is encrypted using Bob's public key
  5. Let Kb- be the private key for Bob, and Kb-(m) be the function expression which indicates the message, m, is encrypted using Bob's private key
  6. Let Ka+() be the inverse function of Ka-(), so Ka+(Ka-(m))=Ka-(Ka+(m))=m
  7. Let Kb+() be the inverse function of Kb-(), so Kb+(Kb-(m))=Kb-(Kb+(m))=m
  8. Let H() be a hash function

QUESTION: If Alice wants to send a message that only Bob can read, AND that Bob can know that the message must have come from Alice, what message does she send?

Kb-(m, H(m))
Kb-(Ka+(m))
Ka-(Ka+(m))
Kb+(Kb-(m))
Kb-(Kb+(m))
Ka+(Ka-(m))
Kb+(Ka-(m))
Ka+(Kb-(m))
Ka-(Kb+(m))
Solution by an expert tutor
Blurred Solution
This question has been solved
Subscribe to see this solution