In a system using public-key cryptography, site B wants to fool C by impersonating A. B waits until A requests to communicate with B. A does this by sending an “I want to communicate” message to B, stating its name (A) and encrypted with B’s public key. Then B springs the trap. It sends an “I want to communicate” message to C claiming it is A and encrypted with C’s public key. To ensure that it is actually communicating with A, C replies (to B) with a message obtained by encrypting a large random number, N , w ith A’s public key. If C gets a response containing N + 1 encrypted with C’s public key, it would like to conclude that the responder is A because only A could have decrypted C’s message. C gets such a response. However, this conclusion is wrong because the
response comes from B. Explain howthis could have happened. (Hint: The protocol can be corrected if the encrypted text of each message includes the name of the sender.)
What will be an ideal response?
C replied to B (thinking it was A). When B gets the encrypted message, containing N , it cannot decrypt it, but it sends the message to A using the same protocol. A ecrypts the message and encrypts N + 1 w ith B’s public key since it is trying to complete the protocol with B. B decrypts the message, re-encrypts it with C’s public key, and sends it to C.
If the protocol requires that the encrypted text of each message includes the name of the sender, A would know the message it received from B was constructed by C and not by B.
You might also like to view...
Rotating arranges a list of words in ascending order or in descending order .
Answer the following statement true (T) or false (F)
When an argument is passed ____, you are passing a reference to the variable that holds the value instead of the value itself.
A. ByRef B. ByHand C. ByVal D. ByVar
An input, such as a cell reference or value, needed to complete a function.
What will be an ideal response?
A channel added to manipulate, protect, or isolate colors in a specific area is called a(n) ____________________ channel.
Fill in the blank(s) with the appropriate word(s).