In this Crypto System to Network we propose a new data encryption algorithm based on private key (symmetric key) cryptography method.The volume of network traffic over the Internet is exponent daily due to increase in communication through E-mails, small branches remotely connect to their corporate network and commercial transactions. Hence protection of networks and their services from unauthorized modification and destruction is very much needed.TCPIP is the most commonly used communication protocol in the Internet domain. IP packets are exchanged between the end hosts as plain text (without any encryption). As Internet uses Packet Switching Data Network anybody who can access to Packet Switching Data Network can change the data. Hence securing data over the network is difficult. The goal of network security is to provide, authenticity, confidentiality and integrity. Confidentiality is making sure that no body other than the receiver will be able to read the data. Integrity is must and data didnt get modified by some other means while data transmitted. Authenticity is making sure that the data is coming from the correct source.In this Paper using crypto method, Keys are shared between two end hosts using Diffie-Hellman algorithm. Cyber block chaining method is used while encrypting/decrypting the data. More prime numbers are generated well in advance and kept for further key refreshments. Periodically keys were refreshed, so it does not give the time to hacker to attack the system. As simple operations are used, we will be able to achieve fast and secure data encryption/decryption using this method. The proposed approach is verified through various tests.