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Bacon Cipher: Encode and Decode in A and B Groups

This free Bacon cipher tool writes each letter as a group of five A and B symbols, and decodes groups back into letters. It can use A and B or the digits 0 and 1.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is It and When Do You Need It?

Bacon’s cipher turns each letter into five A or B symbols. It is a binary code from 1605, four hundred years before computers. A was 00000 and Z was 11001 in the 26-letter version.

Encode a message, or paste groups of A and B to read one.

How to Use This Tool

  1. Type text or paste Bacon code.
  2. Choose the direction and the symbols.
  3. Press Run.
  4. Copy the result.

How the Calculation Works

Each letter A to Z is numbered 0 to 25, and the number is written in five binary digits with A for 0 and B for 1. Decoding reads five symbols at a time, converts them to a number and then to a letter.

Worked Example

HELLO becomes AABBB AABAA ABABB ABABB ABBBA.

Common Uses

  • Puzzles and geocaching.
  • Teaching binary.
  • History of cryptography.
  • Escape rooms.

Tips and Common Mistakes

  • The groups must have exactly five symbols.
  • Use 0 and 1 to see the binary directly.
  • Spaces and punctuation are not encoded.
  • Some versions of the cipher treat I and J, and U and V, as the same letter, giving a 24-letter alphabet, so check which version your puzzle uses before decoding.

Next, you may need the A1Z26 cipher, Polybius square, NATO alphabet, Caesar cipher.

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Frequently Asked Questions

Invented by Francis Bacon in 1605. Every letter becomes a group of five symbols that are each A or B, which is really a 5-bit binary code.
The 26-letter version, where every letter has its own code (I and J, and U and V, are different).
Bacon planned to hide the A and B signals in two typefaces of an innocent text, so the message itself is hidden.
Paste groups of five A and B symbols. Spaces between groups are optional.

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