[Gene Eric]

I believe this is the relevant clause:

nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law

And I don't see anything related to warrant.

Consider the case of the missing body where the defendant takes the 5th. Is the defendant still obliged to specify the location of the body as it may provide evidence of the alleged crime?

I'm not remotely educated in criminal law. Just curious if you see any parallels between knowledge of the missing body and knowledge of the missing password.

[Moltke]

And I don't see anything related to warrant.

Well, there is that without due process of law part at the end...perhaps a warrant is part of the legal due process?