While symmetric encryption uses a single key that needs to be shared among the people who need to receive the message, asymmetric encryption uses a pair of public key and a private key pair to encrypt and decrypt messages when communicating. Symmetric encryption is an old technique while asymmetric encryption is relatively new. Asymmetric encryption was introduced to complement the inherent problem of the need to share the key in a symmetric encryption model, eliminating the need to share the key by using a pair of public-private keys.