You need to add "assuming you are willing to go to jail" because a warrant can compel you to disclose your password, and if you refuse you'll be jailed for contempt of court.
That'd be thrown out of courts as a violation of your 5th Amend. rights. At least here in the states, in the UK crypto keys can be requisitioned with the penalty of jail time if refused.
I believe some rulings support that view, but others have disagreed. It might depend on the judge/district and I don't think it's ever been considered by the Supreme Court.