Recently I have been thinking about hiding various items, even though I have no specific reason to look for hiding anything from anyone. But the idea is attractive, you can encrypt digital information but not physical objects, which can only be locked up or hidden to prevent unwanted access. I'm looking for ideas for hiding appropriately sized physical objects. I realize it's a rather open question, hiding what, where and from who and so on, that's why I will specify and restrict the question further.
I'm interested in hiding spaces that can be accessed relatively often, about once every week or month. This should be the only limiting factor as to where we are hiding things. It could be our own property, car, or some place we often visit.
Hiding very small items is easy and it's often not very useful. And any object we are looking to hide should be transportable by a single person. So in terms of order of magnitude, I'm interested in hiding spaces ranging from 1 liter (33 oz) to 10 liters (2.6 gal). In terms of examples, we could be hiding a few bars of gold or a handgun. Too small: An SD card, a key. Too large: A fire axe, a car.
Now, perhaps most importantly, who are we hiding things from? I believe there are a few levels of opposition we might be facing, and while I'm not trying to be comprehensive, I will roughly seperate them into four categories:
0. Not searching person - someone trivially stumbling into your hidden items.
1. Not experienced, not dedicated person searching (e.g.: family member looking for drugs).
2. Experienced, dedicated person, searching with limited time (e.g.: burglar looking for gold).
3. Experienced, dedicated person(s) with lots of resources, searching without any time limit. (e.g.: police looking for evidence).
I think whatever the situation is if there is a good chance of failing against Case 0, it's a terrible hiding spot from the start. Many "hidden in plain sight" ideas kind of fall into this category. For all opposition except for Case 0, we assume the opposition knows what they are looking for. It's preferable if the hiding place can thwart tough opposition, Case 2 or 3.
As you can see, it's an optimization problem with many variables and without any clear answers. Any discussion is welcome.