Bacon Cipher
Hide letters as five-character A/B or 0/1 groups, with vowel, case, atbash, prime, odd/even, enclosed-shape, and custom-key decoders.
Francis Bacon's cipher hides one message inside another. Originally each letter was carried by switching between two typefaces; today we usually write the carrier as A/B or 0/1. This tool encodes plaintext to Bacon and decodes many disguised forms — case-sensitive, vowels vs. consonants, prime letters, even/odd, enclosed-shape glyphs, the half-alphabet (Atbash) split, or any two characters you choose. If your ciphertext already has only two unique characters, the decoder will pick them up automatically.
Case
Filter
Whitespace
Find & Replace
Group
Decoders read groups of five carrier symbols. Use the swap buttons if the polarity is reversed.
Case
Filter
Whitespace
Find & Replace
Group
Decryption modes explained
Auto-detect 2 chars: if the ciphertext has exactly two unique characters (after removing spaces), they are mapped to A and B automatically.
Normal: classic A/B or 0/1 carriers.
Case: uppercase letters are A, lowercase are B (the original Baconian typeface trick).
A–M vs N–Z: the alphabet is split in half — first-half letters/digits are A, second-half are B.
Vowels vs consonants: vowels are A, everything else is B.
Enclosed shapes: letters and digits with closed loops (a b d e g o p q 0 4 6 8 9) are A, the rest B.
Even vs odd: digits and letter positions evaluated for parity — even is A, odd is B.
Prime vs non-prime: prime letters and digits (2 3 5 7 B C E G K M Q S W) are A, the rest B.
Custom characters: pick any two characters from your ciphertext to map to A and B.