Bacon Cipher
Encode and decode Bacon's cipher. Also detect hidden messages in mixed-case text (steganography).
Bacon Cipher Table (24-letter)
What is Bacon's Cipher?
Bacon's cipher, invented by Sir Francis Bacon in 1605, is a method of steganography (hiding messages) that represents each letter as a sequence of five binary symbols—traditionally 'A' and 'B'. This allows secret messages to be hidden within innocent-looking text.
How Bacon's Cipher Works
Each letter is encoded as a 5-character sequence of As and Bs:
- A = AAAAA
- B = AAAAB
- C = AAABA
- H = AABBB
- E = AABAA
- L = ABABA
- O = ABBAB
The sequence "HELLO" becomes: AABBB AABAA ABABA ABABA ABBAB
24-Letter vs 26-Letter Alphabets
24-Letter (Standard)
The original cipher uses 24 letters where I and J share the same code, as do U and V. This was common in Bacon's era.
26-Letter (Modern)
Modern variants use the full 26-letter alphabet, giving each letter a unique code.
Steganography: Hidden Messages
Bacon's cipher is most famous for hiding messages in plain sight. The classic technique:
- A = lowercase or regular text
- B = UPPERCASE or bold/italic text
Example: "ThIS iS a SecReT" contains the hidden message "BAB BAB" which could decode to part of a word.
Bacon Cipher in Geocaching
Geocaching puzzles often use Bacon cipher because:
- Stealth: Messages can be hidden in cache descriptions
- Visual variety: Can use fonts, colors, formatting differences
- Historical appeal: Connects to cryptography history
- Multiple layers: Often combined with other ciphers
Alternative A/B Representations
Different puzzle creators may use various symbols for A and B:
- 0/1: Binary representation
- ./−: Morse-like notation
- Upper/Lower: Case-based steganography
- Two images: Different pictures or icons
- Two fonts: Serif vs sans-serif
- Colors: Two different text colors
Recognizing Bacon Cipher
Look for these clues:
- Groups of 5: Letters, numbers, or symbols in fives
- Only 2 symbols: All text uses just two different elements
- Odd formatting: Random capitalization or styling
- Length pattern: Hidden message is 1/5 the visible length
Historical Context
Francis Bacon developed this cipher for secret communications. The technique was so effective that scholars have searched for hidden messages in Shakespeare's works and other Renaissance texts, suspecting Bacon himself authored them.
Related Cipher Tools
- Binary Converter: Similar two-symbol encoding (0 and 1).
- Morse Code: Uses dots and dashes, another two-symbol system.
- A1Z26: Simple letter-to-number encoding.