I couldn't point you to a citation but you can google around, courts have compelled lockers to be opened, safes to be opened, and they've compelled people to

I couldn't point you to a citation but you can google around, courts have compelled lockers to be opened, safes to be opened, and they've compelled people to decrypt things. The fifth amendment applies to words you say, not evidence. The "pass phrase" is access to the evidence, not testimony against yourself. It's a losing battle anyways, a judge demands you turn over the passphrase or unlock the data and throws you in jail until you do. You could attempt to take it to the supreme court or something, but you're in jail during that process. Likewise, you could try to give them the wrong key with truecrypt or something but that assumes that they are idiots. If you find yourself in court in this situation, you've already lost, you're almost certainly going to spend time in jail.