Cache Register

Since our illustrious editrix decided to play word games with my last post about caches, a few of the writers here have decided “challenge accepted”. You want prepper puns? We'll deliver them.

If you're going to hide some things far away from your normal Area of Operations (AO), you'll need to have a way to find them when you need them. A map with a large red X on it will work, but it will also mark the spot for anyone else that may see or find your map. I mentioned encrypting the location information in my last post, so here are a few methods that will work toward that end.

Methods of Identifying a Location

First, you need to figure out what kind of information you're trying to hide. The location of a cache (buried, submerged, or otherwise hidden from view) can be expressed as a series of numbers and/or letters using one of many methods. Those letters/numbers can then be encrypted to make it more difficult to find your cache.

Latitude and Longitude
The most common method of designating a specific place on the planet, lat/long has been in use for centuries. Starting from the arbitrary “zero” of the Prime Meridian that passes through Greenwich, England and moving around the earth east and west, we divide the world into 360 one-degree slices. The north-south division begins at the Equator and is also a total of 360°. Each degree is divided into 60 “minutes” (symbol ' ) and each minute is divided into 60 “seconds” (symbol “). A complete lat/long would look like 21 18' 32 ' -157 51' 3” or 21.308787 -157.850811 in decimal form. The negative sign designates areas south of the Equator and/or west of the Prime Meridian. Geo-caching and modern GPS units have made lat long a common system.

Military Grid System
Instead of working with pure numbers, the US military decided to separate the Earth into 60 east-west zones (numbered 1 through 60) and 20 north-south zones (letters C through X, excluding I and O which are easily confused with 1 and 0). Each block designated by a number and a letter is roughly 6° by 8° and covers about 800 km by 1100 km. An example zone would be called “4Q”.

Each block is further split up using 24 east-west and 24 north-south lines, to create squares. These squares are identified using the same letters of the alphabet as the grids. An example would be “FJ”.

Locations within the squares are pinpointed by measuring, in meters, from the south-west corner. You measure the distance east, then the distance north to get a string of numbers. The more precise the location, the more numbers. An example would be “19056562”, which means 1905 meters east and 6562 meters north of the starting point.

Using this system (which takes some practice) and military maps, a chunk of land 10 meters on a side would have a designation something like “4QFJ19056562”, which happens to be somewhere in Honolulu, HI.

Polar Coordinates
Instead of measuring in squares, another method uses vector and distance from a known point. If you have a standard starting point, say a large boulder or a bridge, you take out your compass and note the direction to your cache (the vector). You then measure the distance in paces, meters, feet, etc. and combine the two. An example would be 143275, for a point 275 meters (or feet, whatever you want to use) from your starting point at a bearing of 143°.

Encryption

Now that you have your data, you need to pick a way to hide or encrypt it. I don't have the time or space to get into all of the possible ways you can encrypt numbers, but I can give you a few basics.

Substitution Codes

These are the most common form of encryption. Replacing a letter or a number with another digit, chosen through a system that only you know, is the root of a substitution code. They are as basic as replacing the numbers 0 through 9 with letters of the alphabet starting with the first letter of your middle name (FGHJKLMNPQ for me) and get as complicated as the 128-bit security algorithms used for banking. Pick one that you're likely to remember or that you can pass on to someone else if you're unlikely to be able to use your cache. Replacing letters with numbers is similar. I suggest you look into one-time pads if you're serious about encrypting data.

Steganography 

Another method of hiding or encrypting your data, the quick definition is "placing your numbers and/or letters in an existing document in such a way that they are not noticed" (follow the link for a thorough explanation). Writing your debit card PIN number down as the last four digits of a phone number is a (not very smart) example - anybody that sees it will think it is just a phone number. Writing a lat/long designation in decimal form down in the back of a math book, maybe as part of an equation, would be another example.

Split Control 
This option breaks your data into two parts and gives each part to a different person. John has the longitude or vector, but Mary has the latitude or distance.

Being able to find what you have intentionally “lost” is important. I hope I have given you some things to think about, and maybe a new idea or two. As always, comments here or on our Facebook page are always welcome.