Cryptography is the study and practice of techniques for secure communication in the presence of third parties called adversaries.With the increasing growth in the internet, Network Security has become a big concern and threat for organizations whose private network is connected to the internet. Information security is the most extreme basic issue in guaranteeing safe transmission of data through the web.In order to secure data transmission and network, cryptography and network encryption are used. Cryptography ensures that the content of messages remain confidential. Network Security has become one the major concerns as the world transitions to digital world. Network security provides security for administrator managed data.Network security is setup to guard against unauthorized access, alteration, or modification of information, and unauthorized denial of service. In this paper, we have discussed about cryptography process, security mechanism, security services, attacks, types of cryptography, Steganography.

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Keywords: Cryptography, Network Security.