Simple: You don't invest in Bitcoin/Zerocoin in the first place. Digital currencies are the online equivalent of cash, not of a savings account or stocks. Like

Simple: You don't invest in Bitcoin/Zerocoin in the first place. Digital currencies are the online equivalent of cash, not of a savings account or stocks. Like regular cash, it can be stolen (e.g., by hacking into your computer) or lost (hard drive crash with an outdated backup), and thus, you shouldn't have more on hand than you can afford to lose. Different rules apply to speculators, of course, but you are talking about retirement savings. Putting your retirement savings in a Bitcoin wallet is about the same as having a pile of cash under your mattress.