Question

1.Packet filtering firewalls are usually configured to examine incoming traffic. Give some business reasons why a packet filtering firewall may be configured to inspect outgoing traffic. Help provide bullet points and short explanations to your points please. An outline would be very helpful!

2.in your own words how the dual signature used in SET (Secure Electronic Transfer) protocol differs from a normal digital signature. Please  discuss/hekp outline both the strengths and weaknesses/issues of using the SET protocol for eCommerce.

Answer 1

Packet filtering is a firewall technique used to control network access by monitoring outgoing and incoming packets and allowing them to pass or halt based on the source and destination Internet Protocol (IP) addresses, protocols and ports.

Why a packet filtering firewall may be configured,

Packet-filtering firewalls

Packet-filtering firewalls provide a way to filter IP addresses by either of two basic methods:

1. Allowing access to known IP addresses

2. Denying access to IP addresses and ports

By allowing access to known IP addresses,

For example,

You could allow access only to recognized, established IP addresses, or, you could deny access to all unknown or unrecognized IP addresses.

By denying access to IP addresses or ports,

For example,

You could deny access to port 80 to outsiders. Since most HTTP servers run on port 80, this would in effect block off all outside access to the HTTP server.

SET: the dual signature.

The purpose of the dual signature is to link two messages that are intended for two different recipients. In this case, the customer wants to send the order information (OI) to the merchant and the payment information (PI) to the bank. The merchant does not need to know the customer's credit card number, and the bank does not need to know the details of the customer's order. The customer is afforded extra protection in terms of privacy by keeping these two items separate.

However, the two items must be linked in a way that can be used to resolve disputes if necessary. The link is needed so that the customer can prove that this payment is intended for this order and not for some other goods or service.

To see the need for the link, suppose that the customers send the merchant two messages: a signed OI and a signed PI, and the merchant passes the PI on to the bank. If the merchant can capture another OI from this customer, the merchant could claim that this OI goes with the PI rather than the original OI. The linkage prevents this.