Increasingly I'm convinced that if you want to keep a secret for any reason, the only way to do it these days is encrypted on an SSD that will physically self-destruct without regular maintenance of the "kill switch" (also cryptographically secure). It should do this on a regular enough basis that you could withstand the stay in a cell, but long enough that an unexpected weekend in the hospital doesn't wipe out your data.

The thing is that you must have this as your standard practice... you can't just adopt it when the feds kick down your down.