SSH
Using the SSH protocol, you can connect and authenticate to remote servers and services. With SSH keys, you can connect to GitHub without supplying your username or password at each visit.
Symmetric encryption
In symmetric encryption, you use the same key for both encryption and decryption of your data or message. Taking the example I gave above, sending a secure message to your granny, both of you need to have the same key in order to encrypt and decrypt the messages that you may exchange with each other.
Asymmetric encryption
Asymmetric encryption is quite the opposite to the symmetric encryption as it uses not one key but a pair of keys: a private one and a public one.
You use one to encrypt your data, which is called public key, and the other to decrypt the encrypted message, which is called the private key.
Private keys
Your private key, as the name states, is yours and it must be kept private, as it’s the only key that can decrypt any message that was encrypted with your public key.
Public keys
Public keys as, yet again, the name states, are public and thus no security is required because of it should publicly available and can be passed over the internet. The public key is used to encrypt a message that can only be decrypted using, as I written above, its private counterpart.
