In asymmetric encryption, there are two keys, one for encrypting and one for decrypting.
Asymmetric encryption introduced much more flexibility in secure communications as the encryption key is not kept secret.
For example, if a sender, Alice, wants to send a message to Bob, Alice retrieves Bob’s public encryption key, which is made available to anyone who wants to encrypt a message and send it to Bob.
She then encrypts the message with Bob’s key prior to sending the ciphertext to Bob.
Only Bob can decrypt the ciphertext using his private decryption key, which remains secret.
With symmetric encryption, we had the challenge of establishing a secure channel to share the secret encryption/decryption key prior to the encryption process.
This constraint is removed in asymmetric encryption.