Cryptosystems can be of two types:

• Asymmetric Cryptosystems

• Symmetric Cryptosystems

ASYMMETRIC CRYPTOSYSTEMS

In an asymmetric cryptosystem (or public key cryptosystem), there are two different keys used for the encryption and decryption of data. The key used for encryption is kept public and so as called public key, and the decryption key is kept secret and called private key. The keys are generated in such a way that it is impossible to derive the private key from the public key. The transmitter and the receiver both have two keys in an asymmetric system. However, the private key is kept private and not sent over with the message to the receiver, although the public key is.

SYMMETRIC CRYPTOSYSTEMS

Asymmetric cryptosystem (or private key cryptosystem) uses only one key for both encryption and decryption of the data. The key used for encryption and decryption is called the private key and only people who are authorized for the encryption/decryption.

#### Public key cryptography is generally slower than symmetric cryptography, and unless the person doing the encrypting and the person doing the decryption are different there is no point in using it. In fact, when using public key cryptography it is common to only encrypt a symmetric key with it, that in turn is used to encrypt the data being sent