Passwords, The Fifth Amendment, and Thumbs
How does the fifth Amendment apply to passwords you might ask.
Let’s say that the police want to perform an inspection. Perhaps you had a baggie of oregano in your car and they take an interest in you. 
There is a laptop sitting on the back seat. Now, the police are thinking: I wonder what this citizen is into. So they decide to power it up and take a look. If you are smart, and you are protecting your company’s secrets and VPN access, and your banking information you have set a password. Good you. Well done.
The police now cannot get into your laptop. And, they cannot ask you for the password. Your privacy and your company’s privacy are protected. Even a judge cannot ask you for the password. This password is protected by the fifth amendment and you cannot be forced to disclose it. Secrets safe.
iPhones, iPads, and newer computers have thumbprint readers. You think they are safer? Think again!
Your fingerprints are not protected by the fifth amendment. (See http://www.macrumors.com/2014/10/31/fingerprints-not-protected-by-fifth-amendment/ and http://time.com/3558936/fingerprint-password-fifth-amendment/).
This means that the police officer can ask you to touch the fingerprint scanner to unlock your laptop and take a look at all of your files. If you have a word document containing all of your passwords, they can then log into all of your online accounts and take a look. You have no protection and no rights.
The rule is:
The fifth amendment protects what you know, now what you possess.
Our company has a policy that we don’t use fingerprint login devices. They are just not as secure as a good password system.