Abstract: Network security and cryptography has received much attention in the recent past. As with the increasing threats, viruses and risks, number of people need to understand the basic security structure of network and the methods to deal with it. One of the approach is cryptography which is being discussed here. By this method we can secure information which cannot be understand or visualised by the human system. Using different cryptographic approaches we can share the message secretly to one another within the network. Network security policies are controlled by the administrator of network and it is used to provide authentication and authorization in order to access in a network for data. This study, presents an overview of various cryptography algorithms and further a comparison based on the various parameters.