Cryptosystem Classification

Fundamentally, there are two types of cryptosystems:

• SYMMETRIC CRYPTOSYSTEM It is a cryptosystem where the same key is used for encrypting and decrypting the information.

As shown above, the sender uses a KEY to encrypt the PLAINTEXT and sends the CIPHERTEXT to the receiver. The receiver uses the same KEY to decrypt the message. Because a single key is used, this system is named as symmetric cryptosystem.

• ASYMMETRIC CRYPTOSYSTEM It is a cryptosystem where two different keys are used for encrypting and decrypting the information.This type of cryptosystem is also known as public key cryptosystem.

As shown above, the sender uses a KEY (public key) to encrypt the PLAINTEXT and sends the CIPHERTEXT to the receiver. The receiver uses another KEY (private key) to decrypt the message. Because two different keys are used, this system is named as asymmetric cryptosystem.