Letter extractor
Extract hidden letters by positions, patterns, masks, or common attempts.
Paste a text, choose an extraction rule, and automatically retrieve the matching letters, digits, or characters. The tool helps test hidden messages, acrostics, simple transpositions, and light cryptography clues.
Source text
Settings
Scope
Processed text
Extraction mode
Result
Quick explanation
Choose the processing scope, the type of characters to analyze, then the extraction mode. The result updates automatically and can be copied or downloaded as a TXT file.
Try this too
Need a simpler interactive extraction tool?
Use Text mask to extract every Nth letter, exact positions, a range, or a binary pattern with automatic recalculation.
Additional information
How to use the letter extractor
This tool helps you quickly test extraction methods often used in riddles, hidden messages, and simple cryptography exercises. Paste a source text, choose what should be analyzed, then select a rule: the result updates automatically.
1. Choose the scope
All treats the text as one sequence. Lines applies the rule to each line. Words restarts the extraction for every word.
2. Clean the text or not
Letters/digits removes spaces and punctuation. Letters keeps only the alphabet. Raw text keeps characters as they are.
3. Read the result
The result may become a word, a short sentence, or a clue to test in another tool, such as A1Z26 if you get a number sequence.
| Mode | Use | Example |
|---|---|---|
| 1 in N | Takes one character every N characters, with an adjustable starting point. | 1 in 2 keeps the 1st, 3rd, 5th… |
| Positions | Extracts only the listed positions, counted from 1. | 2,4,6,8 retrieves even positions. |
| Pattern | Repeats a list of positions in each block. Useful when a hidden message follows a regular rhythm. | 1,3,5 keeps three positions in each block of five. |
| Mask | Uses a string of 0s and 1s: positions marked 1 are kept. | 010110 keeps characters 2, 4, and 5 in the pattern. |
| Reorder | Rearranges each block according to the requested order. This helps test a simple transposition. | 5,4,3,2,1 reverses each block of five. |
| Hints | Shows several common attempts at once to explore a suspicious text quickly. | 1 in 2, 1 in 3, masks 10, 01… |
Tips for beginners
Start with Letters/digits and All when analyzing a compact sequence. If the message looks like an acrostic or a list, try the Lines scope. For a sentence where each word may hide a letter, the Words scope is often more relevant.
This kind of extraction does not truly encrypt a message: it reveals information hidden in a structure. To solve a puzzle, test a simple rule, see whether the result becomes readable, then adjust the starting point, pattern, or scope.
Limits and reuse
AppErgo tools are provided free of charge for practical and informational purposes. Although care is taken in their design, a result may be incomplete, unexpected or incorrect. Before relying on a result for any important use, check it using an appropriate method.
To report a bug in the tool, you can use the dedicated bug report form.
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