Chapter 9, Problem 11PE

Explanation of Solution

Effects:

• The major problem with digital certificates is that there is no way for withdrawing them.
• For example, a person “P” claims to be a staff member of an organization “O1” and obtains a new public key certified by the certifying authority “CA”.
• Assume the certifying authority “CA” believed incorrectly that “P” was acting on behalf of an organization “O2”, and it gave person “P” a certificate “cert”.
• Now, the person “P” can communicate with a person “V” who verifies the “cert” provided by “P” and trusts that the public key in “cert” really belongs to the organization “O2”.
• The person “P” can now communicate with “V” employing the public key and the person “V” trusts the communication is from the organization “O2”...