Salesforce supports Encrypted Field out of the box on standard or custom objects. However, users with appropriate profile or permission set can easily view content of those fields. If we want to store secure information like passwords (of external systems), then there is no direct way to achieve this. If we think about passwords, no one should be able to view it. If we forget password, then instead of system sending old password, it forces us to reset it.
We will create same behaviour in Salesforce where stored password cannot be viewed by anyone.