This question already has an answer here:
Let's say you use encryption on your computer, and you've been arrested. The police believe there is evidence on your computer, and have seized the computer via a warrant. The police cannot extract any information because your hard drive is encrypted. The police were unable to find the password via other means (such as written notes). You are aware that there is incriminating evidence on your hard drive, so you do not give up the password willingly.
Can the police get a court order or otherwise legally compel you to provide the password to decrypt your hard drive?
(I imagine this would implicate your right to refuse to answer questions that could incriminate yourself.)