What is Encryption and Decryption?

We as a normal Internet user tend to send and receive a lot of information from one system to another system over the Web. The Information that we are sending to someone should only get read by him/her is not always necessary as we know that there might be someone sitting at the sender's computer and the receiver's computer who is just waiting for stealing the information. So how can we protect that if someone is able to steal our information still he/she won't be able to understand the information? This process of hiding information by converting the actual information into some other information by using a key or a piece of code which can not be easily understood by a non-authorized user is known as "Encryption". The Process of converting the Ciphertext (Converted text) into plain text is known as "Decryption". The combined process of Encryption and Decryption is called Cryptography.

The main purpose of Encryption is to maintain the confidentiality of the electronic data that is stored on a computer system or getting transmitted from one computer to another over the network.

Let us take an example, I want to send an email to my friend with the text "Hello", now if I will send the information is in actual form then anyone who is keeping an eye on activities and residing somewhere in my network will steal the information and will be able to understand it easily. So what I can do is I will protect my data and will convert it into something else by using a key. For example, I will change the plain text by using a simple key such as replacing the alphabet by its next alphabet so my text Hello will now become Ifmmp and I will tell my friend the key to converting this text into the actual information.This is a very simple example of how Encryption is performed for converting the plain text into converted text which is known as Ciphertext and the opposite process is called Decryption which will be performed at the receiver's end.

• This is Symmetric Encryption, where the message along with the key is transmitted over the network from source to destination.The main drawback of this type of Encryption technique is that as we are sending message and key together so that If an Intruder steals our message he will get the key as well so now by using this particular key he can open the message and read the information written on it. This is the Concept of Private Key Cryptography. Here the same key will be used for Encryption and Decryption.


• Now in order to get rid of this major drawback the concept of Asymmetric Encryption was developed, in this type of Encryption two keys are there one is Private Key and another one is the Public key. Let us understand this by an example, I want to send some information from my system to one of my friends, now i am having two keys one is my Private Key and another one is Public Key, so what will I do I will acquire a lock on the message that I want to send with Public key which is common for all and will send it over the network, now my friend who has received the message will open the message using his own Private key. Thus in this kind of Encryption, everyone has their own private keys by which only they can decrypt the message and read its content. So now if an Intruder even steals the message he won't be having the private key to open it.This is the Concept of Public Key Cryptography.Here the Public key will be used for Encryption and the Private Key for Decryption.


• Thus in Symmetric Encryption, there is only one key and in Asymmetric Encryption, there are two keys.




An example of a public key associated with one of the Websites, It is possible to see this by examining the information about the URL of a Website.
 

There are various complex Algorithms of Encryption are used for encrypting data such as RSA, DES, AES etc.RSA is the most widely used asymmetric encryption algorithm, on the other hand, AES is used in symmetric encryption.These algorithms are used in the transmission of sensitive information over the web such as our bank-related information, whatever the transmission that we perform between the payment gateway of our bank and an e-commerce site for purchasing a product is completely encrypted to maintain the integrity and security of our account by using any of the algorithms.Our networking devices such as our modem,set-top boxes, smart cards all use encryption or rely on various protocols such as SSH, SSL/TLS to encrypt sensitive data.

Field of Cryptography is very vast as people just keep on working on Algorithms to make them as complex as possible and I hope with this article, I have given you guys an idea about the process of Encryption and Decryption.