Bacon cipher
Encode or decode a message with five-character A/B groups.
Convert text into Bacon code or decode A/B groups, with classic or modern alphabet and live output while you type.
Source text
Result
Settings
Conversion direction
Bacon alphabet
Group separator
Quick explanation
Enter text to encode or a sequence of A and B groups to decode. The Bacon cipher turns each letter into a five-character group, with a classic 24-letter variant and a modern 26-letter variant.
Try this too
Need a reversed alphabet code?
Try Atbash to transform each letter with its opposite alphabet counterpart.
Additional information
How does the Bacon cipher work?
The Bacon cipher represents each letter with a group of five signs. In this tool, those signs are written as A and B. For example, with the classic table, A becomes AAAAA, B becomes AAAAB, and C becomes AAABA.
This system is useful for puzzles, hidden messages, and simple cryptography exercises. It is not modern secure encryption: the goal is mainly to understand a historical substitution and handle binary-like groups easily.
Encode or decode
Encode mode turns letters into A/B groups. Decode mode reads five-character groups and rebuilds the matching letters.
Classic or modern
The classic table merges I/J and U/V, as in many historical presentations. The modern table keeps all 26 letters separate.
Group separator
When encoding, you can separate groups with spaces, dashes, no separator, or a custom separator.
Classic Bacon table
| Letter | Code | Letter | Code |
|---|---|---|---|
| A | AAAAA | N | ABBAA |
| B | AAAAB | O | ABBAB |
| C | AAABA | P | ABBBA |
| D | AAABB | Q | ABBBB |
| E | AABAA | R | BAAAA |
| F | AABAB | S | BAAAB |
| G | AABBA | T | BAABA |
| H | AABBB | U/V | BAABB |
| I/J | ABAAA | W | BABAA |
| K | ABAAB | X | BABAB |
| L | ABABA | Y | BABBA |
| M | ABABB | Z | BABBB |
Concrete example
With the classic variant and space separator, CODE becomes AAABA ABBAB AAABB AABAA. In decode mode, the tool groups A and B characters into blocks of five and replaces each block with the matching letter.
If an incomplete or unknown group is found while decoding, the tool reports partial decoding. This helps spot a copy error or misplaced separator quickly.
Limits and reuse
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