Cryptography

Network security is archived by the cryptography. This is the science based on the abstract algebra. In this article, we will discuss the short terms and also discuss the security of the data that is transferred in a network.

Introduction

First, we will the definition of the cryptography.

Cryptography

Cryptography is a word of Greek origin means “secret writing”. However, we use this term in the science and art for the transform of the message to make them secure and immune to attack.

In the below pic I’ll show you the cryptography components

Plain-text and Cipher-text

The original message, before being transformed, is called a plain text. After the message is transformed this is called cipher text. An encryption algorithm is transformed the plain text to the cipher text. A decryption algorithm is used for decipher the message for the recipient.

Cipher

We refer to encryption and decryption algorithms as ciphers. The term cipher is also used to the different categories of the algorithms in cryptography. This is not to say that every sender and the receiver needs their very unique cipher for a secure communication. On the other side one cipher can serve on millions of communication pairs.

Two categories

we can divide the cipher algorithm in to two groups: symmetric key (also called secret Key) cryptography algorithms and the other is Asymmetric (also called public Key) cryptography algorithms.

Symmetric-key cryptography

In symmetric-key cryptography the same key is used for the both parties. In sender side sender use the and the encryption algorithm to encipher the data: on the other side the receiver use the same key and the decryption algorithm to decryption the data. 

Asymmetric-Key cryptography

In asymmetric cryptography there are two keys used: first one is the public key and the second is the private key. Public key is announced for the public and the private key is only for the receiver. When the message is just about be send the sender use the public key and encryption the data on the other side receiver use the private key and decryption the data.

Comparison

Let us compare symmetric-key and asymmetric –key cryptography.Encryption can be thought of as electronic locking; decryption as electronic unlocking. The sender puts the message in a box and locks the box by using a key; the receiver  unlocks the box with a key and takes out the message. The difference lies in the mechanism of the locking and unlocking and the type of keys used.

In symmetric-Key cryptography, the same key locks and unlocks the box. In asymmetric-key cryptography , one key locks the box, the another is needed to unlock the box.

The security is necessary in the every work of life. Because we all want privacy with our matters. We don’t want that some one interrupt in our work or personal matters. And also computer network is our own privacy that’s why we want that our data keeps safe and secure without any pugs, harm and attacked.

File Transfer

Transferring of data from one computer to the other is the one most common task in networking and inter-networking environment. As a matter of the fact, that greatest volume of data exchange in the Internet today is due to file transfer. We are going to discuss the most popular protocol on Internet that is File transfer Protocol.

Hot spot Technology

Today is the world of technology. Every person has their own mobile phone, laptop and iPod. People lives out of Pakistan or people in Pakistan in different cities they are connected through phone. Firstly we use the phones only for calls, massages and games only. But with the invention of internet we need internet with the phones. That was a very difficult for us but with development of the

Transport Layer Protocol

The original TCP/IP protocol suit specifies two protocols for the transport layer: UDP and TCP. First we will discuss the UDP that is the simpler one then to the other TCP.A new third protocol is also design are STCP.

User Datagram Protocol (UDP):

The user datagram protocol (UDP) is also called as connectionless, unreliable transport protocol. It does not add anything to the services of IP except to process to process communication. If we say that, why would we want to use is it? There are many advantages of UDP other than disadvantages.

Virtual LAN

LAN is a type of network. That we have studied.

A computer is considered as the part of the LAN if it is physically connected to the LAN. What happed if we want a virtual connection between two computers belonging to the two different LANs?

We can define the VLAN as:

Network Backbones (Devices)

Two or more computer connected to each other makes a network. Computers are not individually connected to one another. Some other devices that connect and Internet, we call that devices network backbones. These make the LAN. Backbones help the network to share the data. Data that are share in a network are in different forms. Backbone devices work on highly complex data that is share in the network. Backbone devices are work on different layers of Network Model.

Transmission

Transmission

Transmission means transfer or movement of something from one place to another place. In past pigeons were used to transfer the message from one place to the other. With the changing of time another source is used a man that had horse take a message and go to the place personally where the message is dropped. After that a post office is developed and also the transport facility had introduced a man who wants to transfer his message from one place to the other set his envelop in the post boxes. A currier boy picks that envelops and transfer that messages to the destination.