Asymmetric Cryptography is also called public-key cryptography. The big advantage is that there is no need to share a secret key anymore, because we are able to generate two keys. A public key: Used to encrypt plain text. A private key: Used to decrypt the cipher text from above.
How it works: Jack generates a pair of keys. He publishes his public key. Jones retrieves the public key from Jack and encrypts his important message with it. Jack receives the cipher text from Jones and can decrypt it with his private key.
There are two major downsides of the Asymmetric Cryptography. It takes a lot of CPU and a lot of memory.
The solution is: Use Asymmetric Cryptography to share a secret key.