powershell script to log into sqlplus but hiding the username and password

I am new to this forum and very new to PowerShell.  I need to write a script that logs into an oracle database and looks at a table.  I need a way to hide the user name and password so it is not plain text in the script.  I was thinking maybe having the user name in one file encrypted and the password in the other encrypted and in my powershell script it reads the files and decrypts them?  Maybe that's not a way to do it.  Does anyone have any ideas and how to implement it?  Thank you.