Cipher-Block-Chaining MAC (CBC-MAC) is a mechanism where a b…

Cipher-Block-Chaining MAC (CBC-MAC) is a mechanism where a block cipher is used to provide the message authentication functionality as shown in the diagram. There are, however, numerous collision attacks possible on CBC-MAC. One of which was discussed in class where for messages a, b, c: if MAC(a) = MAC(b); then MAC(a||c) = MAC(b||c). How could this vulnerability be utilized for an attack?

Refer to the exhibit. The exhibit shows a small switched net…

Refer to the exhibit. The exhibit shows a small switched network and the contents of the MAC address table of the switch. The switch has recently been purchased and the PCs have recently been connected to the switch.  They have not communicated through the switch yet.  PC1 has sends a frame addressed to PC3. What wil the switch do with the frame?