Here are examples of the word/phrase "authentication" used in a sentence and paraphrased in a sentence...
How did the hacker get the authentication for accessing that computer?
How did the hacker get the log in information for accessing that computer?
Without authentication, you won't be able to access those files.
Without log in info, you won't be able to access those files.
Secure authentication usually consists of a strong and very complex password.
Secure log in information usually consists of a strong and very complex password.
Other Examples...