Has there been a case where the Fifth Amendment protected someone from disclosing a password? I'm not sure that giving up your password is analogous to being forced to testify against yourself.
"I'm not sure that giving up your password is analogous to being forced to testify against yourself."
This one is tricky. It depends on ones beliefs about the true reasons for the anti-self-incrimination laws. If you believe (as I do) that it is a fundamental right to remain silent whenever it could make your situation worse, then it is indeed analogous.
An opposing view is that not being forced to testify against oneself comes from other, more basic reasons. One of the "higher-order" reasons against forced self-incrimination might be that punishment for refusing self-incrimination gives incentive to false self-accusation. This one does not apply to forced revealing of passwords (you cannot falsely self-accuse in this case.)
Edit: Indeed there has been a case, and so far the Fifth Amendment is holding strong: http://cyb3rcrim3.blogspot.com/2010/04/passwords-and-5th-ame...