FIELD NOTES 03
Cipher basics every treasure hunter should know.
You do not need to memorize hundreds of historical ciphers to be dangerous in a puzzle hunt. A small toolkit covers a surprising amount of territory.
Caesar and ROT shifts
A Caesar cipher moves every letter by the same number of positions in the alphabet. ROT13 is the familiar version that shifts by thirteen. If text looks almost language-like or a clue contains a strong number, a shift is cheap to test. Watch for wraparound from Z back to A, and remember that the number may come from somewhere else in the puzzle rather than being stated directly.
Substitution ciphers
In a simple substitution cipher, each plaintext letter is consistently replaced by another symbol or letter. Frequency helps: E is common in English, one-letter words are often A or I, and repeated letter patterns preserve repeated structures. In puzzle hunts, however, the key is frequently hinted by the clue, so do not assume you must solve every substitution from frequency alone.
Indexing
Indexing is one of the most common puzzle-hunt mechanisms. A sequence of numbers may tell you which letter to take from each word or line. For example, a 3 beside a word can mean take its third letter. Always check whether the clue suggests one-based indexing, zero-based indexing, line numbers, word numbers, or letter positions.
Transposition and ordering
Sometimes the letters are correct but arranged in the wrong order. Columns may need to be read vertically, rows reversed, chunks reordered, or text placed into a grid. If the clue's character count factors neatly into a rectangle, or the formatting looks unnaturally regular, test a transposition before reaching for a more exotic cipher.