In a simple one-to-one substitution, every occurrence of a plaintext letter becomes the same ciphertext letter, and two different plaintext letters do not share an output letter. This preserves a word’s equality pattern even when none of its letters is recognizable. Patterns are particularly useful when a puzzle keeps word boundaries and supplies a clue.
Write a pattern in first-seen order
- Give the first letter the number 1.
- Move from left to right. Reuse its number whenever a letter repeats.
- Assign the next unused number to each new letter.
- Separate the numbers with dots so words with more than nine distinct letters stay unambiguous.
| Text | Pattern | Reason |
|---|---|---|
| BANANA | 1.2.3.2.3.2 | B is new, A is new, N is new; A and N then repeat. |
| ANANAS | 1.2.1.2.1.3 | The repeats start at different positions from BANANA. |
| MONKEY | 1.2.3.4.5.6 | All six letters differ. |
| MEET | 1.2.2.3 | Only the two middle letters match. |
| NOON | 1.2.2.1 | The first and last also match. |
Check a pattern-preserving cipher
Atbash changes letters but keeps their relationships
BANANAAtbash; reverse A–Z alphabetYZMZMZYZMZMZ has pattern 1.2.3.2.3.2, just like BANANA. MONKEY can be ruled out as its plaintext under a one-to-one substitution because its six letters are all different. A matching pattern only says a candidate is compatible with these equality constraints; it does not select a unique dictionary word or establish the key.
Test a proposed word across the whole message
Suppose a fruit clue makes BANANA plausible for YZMZMZ. Record Y → B, Z → A and M → N as ciphertext-to-plaintext mappings. Apply those mappings everywhere they occur in the message. Keep unknown letters marked as unknown rather than filling them with convenient guesses. A proposed solution fails if the same ciphertext letter needs two different plaintext letters.
| Proposed check | Result |
|---|---|
| YZMZMZ → BANANA | Compatible: Y → B, Z → A and M → N remain consistent. |
| YZMZMZ → MONKEY | Incompatible: repeated Z would need several different outputs. |
| ABBA → NOON | Compatible local pattern: 1.2.2.1. |
| ABBA → MEET | Incompatible: the two A positions would need M and T. |
Also check the reverse direction. If ciphertext Y already maps to B, a different ciphertext symbol cannot also map to B in a one-to-one alphabet. Keep a two-column ledger or alphabet strip so you can detect collisions. When a guess produces a contradiction, erase that hypothesis and preserve the observations that did not depend on it.
Use the workbench as a notebook
- Open the ciphertext analyzer and select Word patterns. Expand the word-pattern view to compare the sample words.
- Replace the sample with your cryptogram, preserving the original separators. The view lists the first 40 distinct A–Z runs and counts their occurrences.
- Write down a clue-based candidate with the same pattern. Check both directions of its proposed mapping.
- Use the frequency counts and neighboring words as additional evidence. A high-frequency symbol is not automatically E.
- Test every occurrence and re-encode the completed answer with the intended key or rule before sharing an answer key.
Know when the pattern assumption breaks
This method assumes a one-to-one symbol substitution and useful word boundaries. Vigenère can give one plaintext letter several outputs depending on position. Playfair prepares letter pairs and may add fillers. Homophonic systems can use several symbols for one letter. A transposition moves letters, so the apparent words may have no relationship to the original word boundaries.
The analyzer treats every non-ASCII character as a boundary for the word view: an apostrophe splits a contraction, and an accented character splits a run. The pair and triple view uses a different convention, joining all counted letters. Check the original puzzle before interpreting either view. For numbers, Morse or coordinates, use the relevant decoder instead of assuming an alphabetic cryptogram.