Of course you can be compelled to open your safe. Refusal is interfering with an investigation, obstruction, subject to contempt citation, et cetera.

And in the case of encryption keys where there is a valid warrant (which won't be issued for an open-ended "we think something illegal might be there but don't know what" request), the situation is the same. You aren't testifying against yourself when you surrender evidence, in the case that the state can make a reasonable argument that it knows where and what the evidence is.

The state can't compel you to "give us everything you have so that we can look for something illegal, even though we don't know what to look for or where it is." That's an entirely separate issue and is both an illegal seizure and, if related to a prosecution, possibly a Fifth Amendment violation as well. In other words, the state can ask and require you to cooperate in this situation:

"We have reason to believe that the computer you possess that contained numerous references to bomb-making materials and which we seized as part of your arrest for illegal possession of destructive devices CONTAINS encrypted files with additional relevant information. What are the encryption keys for this data?"

The state can't ask you to answer these questions:

"Have you ever been involved in terrorist activities?" (-- self incrimination)

"Do you have any data in your possession that relates to terrorist activities?" (-- also self incrimination)

"Although we found no evidence of terrorist activities when we conducted a search of your home, and no one in the investigation mentioned your involvement, we wonder if there might be evidence of illegal activities hidden on your computer. Give us the encryption keys." (-- no probable cause)

"We have been searching every 10th computer brought into this Federal building as a matter of routine. Give us the encryption keys." (-- no probable cause although you could be refused entry in most cases.)

Turning over evidence in your possession is not the same as testifying.

Earlier this year, a Vermont court found that a Canadian man's refusal to provide encryption keys for data on his laptop was not protected by the Fifth Amendment.

http://web20.nixonpeabody.com/np20/np20blog/Lists/Posts/Post.aspx?ID=298

This really isn't any different than a situation where a witness or suspect is required to open a safe, provide account numbers, et cetera. In general the state can't "fish" for evidence (say, seize a laptop just to see if it contains anything of interest, without a specific goal in mind), but if there is a reasonable belief that a search will produce evidence that pertains to the charges at hand, the state has the right to conduct the search and compel a defendant to cooperate.

You can always refuse anyway.

I wish I could mod this up today.

So, I understand that people might feel like Google is scanning your library card every time you borrow a book. But the thing is, in order to return more relevant results for your searches, Google (or whoever) needs to know what sort of things you typically look for. You know, like the librarian who tells you that there's a new book on adult stuffed animals.

Relevant search and anonymous search: Pick one.