Hybrid Cryptosystem

 Hi folks ! Hope you are doing great.

In this blog study, we will going to discuss about hybrid cryptosystem.

Hybrid Cryptosystem : A process when we combine symmetric as well as asymmetric cryptosystem together, the obtained system is called as a hybrid cryptosystem. 

- In hybrid cryptosystem, a random secret key for symmetric cipher is generated and then encrypt this key via an asymmetric cipher using the receiver public key.

- The message itself is then encrypted using the symmetric cipher and the secret key. 

- Both the encrypted secret key and the encrypted message are then sent to the receiver. 

- The receiver decrypts the secret key first, using his/her own private key, and then uses that key to decrypt the message. 

What is the need of Hybrid Cryptosystem : As we know that single symmetric as well as only asymmetric key encryption cannot provides full security in some specific area like when the key size is large and we need authentication. In such kind of areas hybrid cryptosystem plays a significant role. 

Like : privacy, authenticity, integrity, non-repudiation, speed. The mentioned features cannot achieved by using single symmetric or asymmetric encryption. That's why we need a hybrid approach.

Example : Let us consider a hybrid approach where we are going to apply the AES and RSA algorithm together. For the working of AES and RSA please study the mentioned link of my previous blog. (https://akshitaggarwaliiit.blogspot.com/2021/11/advance-encryption-standards-aes.html, https://akshitaggarwaliiit.blogspot.com/2021/11/public-key-cryptography-and-rsa.html). Figure 1 describes the functionality of AES and RSA. 


Fig. 1 : A hybrid approach of AES and RSA.

In the above approach a document is encrypted using AES key and then on the receiver side document is decrypted using AES along with RSA key. 

Hope you enjoyed the knowledge of hybrid cryptosystem. If you have any doubt fill the comment section. 😉



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