What is cryptography in Networking?

What is cryptography in Networking?

Cryptography is used for Security Purposes in Networking.

Definition: It is the way of transforming messages to make them secure against attacks. It is a Greek word which means “Secret writing”

Components of Cryptography

1.Plain Text: This is the original message that  is not transformed yet. For message transforming first we will have an encryption algorithem that transforms plaintext into cipher text.

2.Cipher Text: After the message transformed is known as cipher text. Again message is converted from cipher text to plain text through an algorithem known as decryption algorithem.

3.Cipher: We refer both encryption and Decryption algorithem as cipher.

4.Key: A key is a number that the cipher used and operates on. For encryption we use encryption algorithem, plain text and encryption key , these will create a cipher text. While for decryption we use Decryption Algorithem . Decryption key and Cipher text and this will result in Plain text.

5. Alice , Bob and Eve

Alice is the person who sends the secure data. Bob is the Person who is being received the data or message. While eve is the person who intercept the data or make any change in it.

Categories of Cryptograph

It has two categories

1.       Symmetric key Cryptography(Secret key cryptography)                 

2.       Asymmetric key cryptography ( Public key cryptography)   

1.       Symmetric key Cryptography

In this type of cryptography same key is used for both encryption and decryption. Sender uses this key and  an encryption algorithem to encrypt the data  and the receiver also uses the same key and a decryption algorithem to decrypt data.

Note: Encryption is that when plain text converted into cipher text while Decryption is that when  cipher text is converted back into plain text.

2.       Asymmetric key Cryptography

In this type of cryptography two different keys are used a private key and a public key. Private key is used for  decryption and is kept by the receiver. While public key is used for decryption and is kept by the public.  

Continued in next lecture………….