Tools / Bacon Cipher

Bacon Cipher Decoder

Sir Francis Bacon’s cipher encodes each letter as five A/B symbols (5 bits per letter). The fun version in CTF challenges hides those bits inside ordinary text -uppercase vs lowercase, vowels vs consonants, bold vs italic. This tool decodes raw A/B and falls back to case-based and vowel-based plans automatically.

Input

Output

Output appears here.

The 24-letter Bacon table groups I/J and U/V; this tool uses the modern 26-letter version. Decrypt mode tries strict A/B input first, then falls back to case-based and vowel-based plans for hidden-bit puzzles.

How it works

Each letter A-Z maps to a 5-bit code. The classic Bacon table (24 letters, treating I/J and U/V as the same) is rare in modern CTF; almost everyone uses the 26-letter variant which this tool implements. Watch for: paragraphs of text where exactly some letters are capitalized, every fifth word italicized, or two distinct-but-similar fonts. Each is carrying one bit.

For pure A/B input where length is not a multiple of 5, double-check that you have not stripped delimiters too aggressively. For unknown ciphers, paste the input into the Cipher Identifier.