WHAT IS CRYPTOGRAPHY | CLASSIFICATION OF CRYPTOGRAPHY

WHAT IS CRYPTOGRAPHY?

Hello Guys, welcome back to Black'n'White. Today I am going to share information about a very important term in Data security that is Cryptography. 

Introduction to Cryptography: Actually, when we talk with a person which is anywhere in the world we want to secure our whole conversation. Cryptography helps us to do this. Cryptography allows us to securely protect our data which we don't want anyone excess it is used to protect corporate secrets and personal information to guard against things like identity theft and 

Let's take a simple example to better understand suppose there are two persons user_1 and user_2 they are at a different corner of the world and they are talking with each other using the internet. They both want their conversation to be secure but there is one another guy, an attacker who secretly got access to our communication channel. So this guy got access to our communication channel he can do much more than just eavesdrop. So how the user_1 sure that nobody could access this conversation and the goal is to make the conversation secure and here Cryptography comes in. So basically what is it means? Cryptography is a practice and study of techniques for securing communication or we can also say this as, cryptography in network security.

HOW CRYPTOGRAPHY WORKS

The text message first convert in numeric form and then using an encryption key which contains some Algorithm for encryption encrypt previous numeric value we get a ciphertext and now this ciphertext sends across the network to the other side of the world where the other person whose message is intended for used a decryption key and decrypt the ciphertext and then he will get what we actually sent as a message or maybe he gets an error. 

Now let's see how cryptography can help secure the connection considered the above example user_1 send message to user_2 using the internet. Suppose user_1 type 'Xyz' first this text message converted to a numeric value which is an unreadable form then by applying encryption algorithm by the encryption key it is converted to a new value in cryptography we called this ciphertext now we send this encrypted message or ciphertext to the communication channel user_1 is not worried about attacker in the middle who discovering the private message if someone manages to discovers the messages he can not able to decrypt the message without any proper decrypt key to unlock the message. 

Suppose attacker discover the message and somehow he manages tampers with the message and now the message reaches user_2 now user_2 need a decrypt key to converting this unreadable form of a message to readable form so by using this key user_2 convert the ciphertext to a plain text or readable text and it appears on the screen or it get some error. Now, this error is very important the error in the sense tells us the attacker tampered with the original message. Now in modern cryptography, the security of the system purely relies on keeping the encryption and decryption key secret.

CLASSIFICATION OF CRYPTOGRAPHY

1. Symmetric Key Cryptography:-

    It is a system in which both users, sender, and receiver of the message share a single or common key to encrypt the message to ciphertext and decrypt the message to plain text. Data encryption standard (DES) is one of the most popular Symmetric Key systems.

• Classical Cryptography

(a). Transposition Cipher:- 

In this method, the ciphertext is constituted of the permutation of plain text. Actually, it's a method of encryption through which position held by units of plaintext is shifted according to a regular system.

(b). Substitution Cipher:-

It is a method of encryption in which units (single letters, pairs of letters or consisting both and so more) of plaintext replaced with the ciphertext according to a fixed system.

• Modern Cryptography

(a). Stream Cipher:-

In this method, with corresponding digits of the keystream, plaintext digit is encrypted one bit at a time to give a digit of encrypted text.

(b). Block Cipher:-

It encrypts the block of text, rather than encrypting one bit at a time as an in-stream cipher.

Final Words

 Cryptography allows us to securely protect our data which we don't want anyone excess it is used to protect corporate secrets and personal information to guard against things like identity theft. Friends, above I have not discussed classification in very depth but in the future, I also post a separate article that is completely about the classification of cryptography in detail and also on some other topic like working of various cryptographic algorithms and RSA Cryptography. So guys! this is all about Cryptography if you guys have any doubt please discuss it with us in the comment section.