Network Security
Data on the network is analogous to possessions of a person.
It has to be kept secure from others with malicious intent. This intent
ranges from bringing down servers on the network to using people's private
information like credit card numbers to sabotage of major organizations with
a presence on a network. To secure data, one has to ensure that it makes
sense only to those for whom it is meant. This is the case for data
transactions where we want to prevent eavesdroppers from listening to and
stealing data. Other aspects of security involve protecting user data on a
computer by providing password restricted access to the data and maybe some
resources so that only authorized people get to use these, and identifying
miscreants and thwarting their attempts to cause damage to the network among
other things.
The various issues in Network security are as follows :
- Authentication: We have to check that the person who has requested for something or has sent an e-mail is indeed allowed to do so. In this process we will also look at how the person authenticates his identity to a remote machine.
- Integrity: We have to check that the message which we have received is indeed the message which was sent. Here CRC will not be enough because somebody may deliberately change the data. Nobody along the route should be able to change the data.
- Confidentiality: Nobody should be able to read the data on the way so we need Encryption
- Non-repudiation: Once we sent a message, there should be no way that we can deny sending it and we have to accept that we had sent it.
- Authorization: This refers to the kind of service which is allowed for a particular client. Even though a user is authenticated we may decide not to authorize him to use a particular service.