Intentionally making your data inaccessible (by encryption or otherwise) without a means of recovering it to attempt to prevent it being used against you in court could be considered destruction of evidence. If convicted of that, expect far more than a few days in jail, depending on how annoyed the judge is with you.
Typically, you are in trouble when you destroy evidence when you has reasonable cause to believe that it is evidence.
If I delete all of my email today, I'm not committing a crime. But if I find out that my company is being sued for breach of a contract that I was working on, deleting email becomes suspicious.
My attorney has advised me that the best thing in this situation is to have a personal data retention policy: "I delete my email the first monday of every month."
Then, do just that.
If a civil or criminal case is brought against you the law says you must stop any routine houskeeping tasks like that to preserve evidence, but the most you'd have then is 4 weeks worth. Much better than 4 years.
The flip side is I escaped being charged with conspiracy to launder money because I had kept email from several years prior in which I complained at length to my manager about how a particular client was behaving, and then escalated it to his manager. Both managers were implicated, but I could show that I'd reported the behaviour and been reassured by two people who I trusted that nothing illegal was going on.
Actually, I should elaborate: if it were just two people I trusted reassuring me it was fine, I would probably have still been on the hook for contributory negligence. What got me off completely was the fact that the responses I got from the senior manager said that he'd passed all of my information on to the legal team, who'd been over it with a fine-toothed comb and decided it was all above-board. What got HIM in trouble was that he'd never passed it on to legal at all.
