What is difference between symmetric and Asymmetric Cryptography?

The differences between symmetric and asymmetric cryptography are explained below:

Symmetric Cryptography:

Symmetric encryption requires a single key known only to the authorized parties.

Symmetric encryption uses the same key to both encrypt and decrypt.
The most commonly used symmetric encryption algorithms include DES, 3DES,AES, and RC4. 3DES and AES are commonly used in IPsec and other types of VPNs.
Symmetric encryption algorithms can be extremely fast, and their relatively low complexity allows for easy implementation in hardware.
However, they require that all hosts participating in the encryption have already been configured with the secret key through some external means.


Figure: Symmetric Cryptography

Asymmetric Cryptography

Asymmetric encryption uses a pair of keys, one key available publicly (the "public key" and one key k(the "private key" or "secret key" own only to the person the public key belongs to.

Asymmetric encryption uses one key to encrypt and a different one to decrypt. If the owner is encrypting, they use the private key to encrypt and the recipient uses the corresponding public key to decrypt the message. If the owner is the recipient, the sender uses the public key to encrypt and the owner/recipient uses their private key to decrypt.
The most common asymmetric encryption algorithm is RSA.
Compared to symmetric encryption, asymmetric encryption imposes a high computational burden, and tends to be much slower. Thus, it isn't typically employed to protect payload data. Instead, its major strength is its ability to establish a secure channel over a non-secure medium (for example, the Internet). This is accomplished by the exchange of public keys, which can only be used to encrypt data. The complementary private key, which is never shared, is used to decrypt.