This reminds of the adage "We only lose what we don't backup."
Scattered in the reviews of such apps are the occasional "Lost Everything." This could be pilot error and I'm going with that since "We only lose what we didn't backup."
I've been reading up on Secret Apps - the ones that look like one app, but are actually something else. Did you try any of these?
I've installed the Private Calculator + Secret Photo Vault and I'm happy with it, but I was just wondering if there are any better apps for this purpose? Which apps would you suggest?