Tools for solving geocaching puzzle caches
A set of tools for the awkward part of a mystery cache: the image that obviously hides something, with no clue as to what. There is also a full set for audio files, coordinates and ciphered text. Everything runs in your own browser, and nothing you open here gets uploaded anywhere.
Image & visual forensics
Channel & Levels Explorer
Split an image into its red, green, blue and alpha channels, stretch the contrast and posterise it to make faint hidden shapes visible.
Bit Plane & LSB Viewer
Inspect every bit plane of an image and pull out messages hidden in the least significant bits.
EXIF & Metadata Reader
Read every metadata tag, including GPS coordinates and the embedded thumbnail, which often differs from the picture itself.
File Carver & Hex Viewer
Find whole files hidden after the end of an image, and browse the raw bytes.
GIF Frame Splitter
Break an animation into frames to catch anything that flashes past too quickly to read.
Image Compare & XOR
Difference, XOR or overlay two images to reveal what changed between them.
Zoom & Enhance
Magnify, sharpen and find edges, for the puzzles that write the answer very small in a corner nobody looks at.
Error Level Analysis
Show which parts of a JPEG have been edited, by finding the regions that compress differently from the rest.
3D & Stereo Splitter
Pull apart a red/cyan 3D image or a side-by-side stereo pair, to read each eye's view on its own.
Colour Decoder
Read a grid of coloured squares as text: each colour is three bytes, which often spell out coordinates.
Binary & Tupper Plotter
Turn a wall of ones and zeroes into a picture, or draw the image hidden inside a Tupper's formula constant.
Magic Eye Solver
Reveal the hidden image in a Magic Eye stereogram, without having to cross your eyes.
Coordinates & maps
Audio
Spectrogram Viewer
See a sound as a picture. Messages drawn into the frequency domain are invisible to the ear but obvious on a spectrogram.
Morse Decoder
Turn a recording of beeps back into text, working out the sending speed from the signal itself.
DTMF Decoder
Read the number dialled from a recording of telephone keypad tones.
Text & ciphers
Decode Anything
Throw a mysterious string at every common cipher at once, and see the readings ranked with anything coordinate-shaped at the top.
Coordinate Sniffer
Paste a whole cache page and have every coordinate, half coordinate and suspicious run of digits in it pointed out.
Null Cipher Extractor
Pull the message out of innocent-looking prose: first letters, every nth letter, the capitals, the digits.
Letters & Word Values
Letter frequencies, index of coincidence, word values in several schemes, and anagram checking.
Symbol Identifier
Work out which alphabet a row of strange little symbols belongs to, then read it off the chart.
Where to start with a geocaching puzzle image
If a cache page shows you a picture and says nothing else, work through it in this order. Most puzzles give way at step one or two.
- Stretch the contrast. Open it in the Channel & Levels Explorer and press Auto levels. Text hidden a shade or two from the background appears instantly.
- Look at each channel alone, including transparency. A message written in one colour vanishes in the full picture and stands out on its own.
- Read the metadata. Coordinates are often sitting in the EXIF GPS tags, or in a comment field, entirely unencrypted.
- Check the bits and the bytes. If the picture itself is clean, the message may be in the least significant bits, or in a whole file appended after the end of the image.
A quick sanity check before you go too deep: the final coordinates of a mystery cache have to be within two miles (3.2 km) of the posted ones. If what you have decoded lands further away than that, it is not the answer. The Coordinate Toolkit will tell you the distance between any two points.
That same rule can do the work for you. If the puzzle leaves you with
coordinates like N 51 2A.B70 and you never worked out what the
letters were, the Coordinate Formula Solver will try
every combination and keep only the ones close enough to be real.
If the cache gives you a sound file
The same logic applies: look at it before you listen to it. Open it in the Spectrogram Viewer first, because a recording that sounds like meaningless static very often has writing drawn into it, visible the moment you stop listening and start looking. Beeps are usually Morse, and a recording of a phone being dialled is DTMF, which decodes straight back to digits.
If it is a string of gibberish instead
Paste it into Decode Anything, which runs every common cipher over it at once and floats anything coordinate-shaped to the top. If it is a row of strange little glyphs rather than letters, the Symbol Identifier will tell you which alphabet you are looking at. And if the listing itself reads oddly stilted, the answer may be in the prose: try the Null Cipher Extractor on it, or scan the whole page for coordinates you skimmed past.
Nothing is uploaded
Every tool here decodes and processes the file in your own browser. No image, audio file or block of text you open leaves your machine, there is no account to make, and none of it is free only for the first few tries. That also means it is safe to use on a cache you have not published yet.