Question

1. a. Upon a risk analysis on a company's site network, some threats are identified. These include threats from malicious code (i.e. virus, worms and Trojan horse) and threats from denial of service (DoS) attacks. To address these threats, an administrator in the company, Bob, has suggested using a firewall to control the access of the site network from the Internet. i. Contrast the three types of malicious code, virus, worms and Trojan horse. ii. There are three types of firewalls to choose from: packet filtering firewalls, stateful packet inspection firewalls, and application gateways. Describe the working mechanisms of the three types of firewalls. Comment on the effectiveness of using the different types of firewall to counter the threats of virus, worms, Trojan horse and DoS attacks. You should justify your ili. answer In the same smartcard application, you also need an externally stored integrity protected queue (FIFO). You decide to protect each externally stored record with a MAC for which a new key will be generated whenever the FIFO is initialised. What check data beyond the MAC key needs to be kept inside the card? What additional check data do you have to add to the records to guarantee the integrity of the FIFO? b. With the aid of a well labelled diagram, briefly discuss Network Security Model. c.

Answer 1

Solution

c)

Trusted third party Sender Receiver Channel Confidential information confidential information Opponent

Message

Actual information is to be transferred from sender to receiver

The two important persons

Sender

Receiver

is the important in this model

Channel

Channel must be initiated by creating a route through from source to receiver by using communication channel

example

TCP/IP

UDP

Whenever it needs to solve security related issues

for protecting the transaction it do the encryption

So Confidential information can be shared

--

answered one question, really sorry for that

please post remaining question separately, love to answer

all the best