There are different kinds of keys. The identities of Alice and Bob are verified in this protocol.
These keys are known to be a kind of related pair of text files and they are often made together as a pair if one makes their Certificate Signing Request (CSR).
Note that the private key is different file that is often used in the encryption/decryption of data so as to sent a file between one's server and the connecting clients.
Learn more about public/private key from
https://brainly.com/question/8782374