B030710154

Security in Network

A computing network is a computing environment with more than one independent processor and maybe multiple users per system and the distance between computers is not considered. Computers and user terminals which are connected to the network are known as network node. I n network user can send and receive message, executing program and obtaining status.

Basic terminology in network

É Node is single computing system in a network.

É Host is a single computing system's processor.

É Link is a connection between two hosts.

É Topology is the pattern of links in a network

Network topologies

1. Bus Topology

To provide a single communication network on which any node can place information and from which any code can retrieve information. One attachment in bus terminology not impacts the other nodes.

2. Star topology

Has switch as a central. The central switch receives all messages, identifies the addresses, selects the link appropriate for that addresses and forwards the messages.

3. Ring Topology

To connect a sequence of nodes in a loop or ring. Can be implemented with minimum cabling.

4. Mesh Topology

Each node can conceptually be connected directly to each other node and routing logic can be used to select the most efficient route through multiple nodes.

Advantages in network computing

· Resource sharing is used to reduce maintenance and storage costs.

· Increased reliability means if one system fails users can shift to another.

· Distributing the workload means workload can be shifted from a heavily loaded system to an underutilized one.

· Expandability is system is easily expanded by adding new nodes.

Disadvantages in network computing

· Sharing, access controls for a single system may be inadequate.

· Complexity, a network may combine two or more systems with dissimilar operating systems with different mechanisms for interhost connection. Complexity of this nature makes the certification process extremely difficult.

· Unknown perimeter is one host may be a node on two or more different networks.

· Many points of attack, access controls on one machine preserves the secrecy of data on that processor. However, files stored in a remote network host may pass through many host machines to get to the user.

· Unknown path may be many paths from one host to another and users generally do not have control of how their messages are routed.

· Label formats differences is a problem which may occur in multilevel systems is that the access labels may have different formats since there is no standard

· Anonymity is attack can passed through many other hosts in an effort to disguise from where the attack originated

Network Security problem area:

Authentication

Deals with determining whom you are talking to before entering into a business deal or before revealing sensitive information

Secrecy

What usually comes to mind when people think about network security

Non-repudiation

Deals with signature

Integrity control

Keeping information is not modified, add or delete by unauthorized user