02 Geocaching-specific cryptanalysis

Or also: And what do I do with this now???

You’ve found the puzzle and are now confused by a mountain of numbers, letters, pictures, signs or the like?

Again, perhaps this attempt to present in a structured way what what I have found could be will help. Please do not take it amiss if I do not provide a link to every term. Often there is not THE site that helps. But often at least the keyword helps to get on the right track.

The first thing you should do is analyse what you have.

  • Letters? Numbers?
  • Only certain ones?
  • How many?
  • Are there groupings? A division into two for north and east? Does the number of digits, numbers or groupings correspond to the usual number of characters in a coordinate (2 times 5 or 13-21 characters, depending on how it is written)?
  • Could it result in written-out number words (4-6 characters long)?
  • Could the beginning be e.g. N52? Or N and E, if the two coordinate parts can be uniquely identified.

Are you looking for coordinates at all? Or a bearing? Or something else entirely?

Does “reverse engineering” work? So to see which coordinate should come out of the encrypted and compare it with the code.

Doesn’t everything help? Then cross-check:

a) Encrypted with password

You have an obviously encrypted text and maybe even a password, but you don’t know what to use to decrypt it? Here is a list of common ciphers that use a password:

  • ADFG(V)X (cipher contains only exactly these letters or 5 or 6 different)
  • Alberti (Two keywords!)
  • AMSCO (Key consists of digits only! )
  • Autokey
  • Beaufort cipher
  • Bifid cipher
  • Four Square cipher (Two keys! )
  • Gronsfeld cipher (key consists of digits!)
  • Kamasutra
  • Larrabee cipher
  • Polybius (results in two-digit number strings)
  • Nihilists (extension of Polybius)
  • Playfair
  • Porta-cipher
  • Transposition
  • Vigenere(most commonly used)

b) binary

You have found something that has two (sometimes 3 for space) different states? 0 and 1. There or not there. White or black. Two different pictures. Colours. Sounds, etc. Hopefully my page on binary codes will help you.

c) 7-segment display

You have numbers from 1-7 or letters from a to g? Or at least that many numbers or letters, that is, seven different states? These are divided into blocks, with no block longer than seven characters and no character in the block duplicated? The minimum size of a block is two different characters? Then it is the 7-segment display, such as on digital clocks. The numbers from zero to nine as a 7-segment block: abcdef bc abdeg abcdg bcfg acdfg acdefg abc (or abcf) abcdefg abcdfg.

Is it about 14 or 16 letters instead of seven? If so, it could be a 14-segment display or 16-segment display.

d) Right-Left-Top-Bottom

Similar to 7-Segment, this variant also draws signs. Place a pencil on a piece of paper in your mind and let it draw from this starting point without setting it down in the respective direction right, left, up or down. Of course, the four letters RLOU could be called something else. You might know AWSD or JIKM from computer games. But there would be four different ones. And the minimum number of a block is again two! The maximum about eight (+/- 1, depending on the character writing). Repetitions are possible, but rare.

e) the periodic table

You have numbers up to 118? Or letters that don’t seem to belong to any word or common encoding? Maybe especially letters like h, he, li, be, b, c, n, o, f? Or blocks of no more than two letters? Then take a look at the periodic system!

f) Code Sun

You’ve got groups of three of no more than four different letters? Then check out the genetic code sun.

g) Numbers and number systems

You have numbers from 0-9 and letters up to f? Then it’s the hexadecimal system. The letters go further than f? Or the numbers don’t even go to 9? Then it could be a different number system. Binary (0 and 1), octal (up to 8), hexadecimal (16) and the duodecimal system (12) are common. But everything else is also possible. Just play with a converter. You can even convert whole text into numbers. For example, the word Nina in “base 32” results in the decimal number: 1097254.

  • If you have a mix of upper and lower case letters, numbers and +/-signs, i.e.: A-Z, a-z, 0-9, / , a base converter should help.
  • You have numbers from 1-26? Then it’s probably just the letter values of the alphabet.
  • Have you got numbers from about 50 to 120? Then take a look at an Ascii table. By the way, N for North is 78, E for East is 69.
  • You have two-digit numbers consisting exclusively of the digits 1-5? Polybiosor tap code?
  • The numbers are from 2-9, possibly 0 and often occur twice and three times? Vanityor mobile phone keyboard!
  • Speaking of mobile phones: You have a series of numbers that just won’t give a coordinate? Maybe it’s a phone number? Or some other coordinate system?

h) letters

  • You have the letters I, V, X, L, C, D in front of you? That’s Roman numerals.
  • You found the letters m, p and f? Then it’s Kenny-speak.
  • Any amount of A and B? See Binary, which is the Bacon cipher.
  • Letter soup? With relatively normal letter frequency? Is it an anagram? Or a letter shift like the rail fence or transposition process?
  • Only 5 or 6 different letters? ADFG(V)X!

i) Further

  • Numbers and letters mixed that don’t seem to fit anything above? Maybe GC codes or numbers of trackables?
  • Numbers and letters mixed, always a number and a letter? Maybe a matrix? Fill a spreadsheet at the respective positions with an X.
  • Numbers and/or letters and/or special characters? Leet-Speek?

You still have no idea? Throw it at a search engine!

And read on in the articles here 😉