CLASSICAL CIPHER WORKBENCH
Explore classical ciphers
Choose one of six historical cipher methods, enter text, and encode or decode it locally in your browser. English and Russian are supported where the selected cipher has a suitable alphabet.
Vigenere and Atbash transform Latin and Cyrillic letters; Polybius offers separate Latin and Russian grids. Playfair and Bacon use Latin-only conventions, while Scytale rearranges any Unicode text.
These methods are useful for learning, puzzles, and demonstrations. Their historical designs are not modern encryption and must not be used to protect sensitive information.
Enter text to transform
Choose a cipher and transform text.
Output
Classical cipher methods and limitations
Select Vigenere, Atbash, Playfair, Polybius square, Bacon, or Scytale from one local text tool. Each method uses a different rule: keyed letter shifts, mirrored alphabets, digraph substitution, coordinates, five-symbol groups, or transposition.
- Vigenere and Atbash: Latin and Russian letters; punctuation remains unchanged.
- Polybius: separate English 5×5 and Russian 6×6 grids.
- Playfair and Bacon: English-only historic conventions with spelling ambiguity.
- Scytale: reversible rearrangement of Unicode grapheme clusters when the column count is known.
Classical ciphers are not secure encryption. Do not use them for passwords, personal information, or confidential messages.
Frequently asked questions
Which ciphers are included?
Choose Vigenere, Atbash, Playfair, Polybius square, Bacon, or Scytale. ROT13 and Caesar are available in a separate tool and are not duplicated here.
Can I use Russian text?
Vigenere and Atbash transform Russian letters, including Ё. Polybius has a 6×6 Russian grid. Playfair and Bacon are Latin-only; Scytale works with Unicode grapheme clusters.
How does the Vigenere cipher work?
A keyword supplies repeating letter shifts. To decode, select the matching action and use the same key; characters outside the alphabets remain unchanged.
What does Atbash do?
Atbash replaces each letter with its mirror in the same alphabet. It needs no key and is its own inverse.
Why does Playfair change J to I?
The classic English Playfair square has 25 cells, so I and J share one. Spaces and punctuation are removed, and X or Q may be inserted to complete pairs.
Does Playfair decryption restore the original spelling?
Not always. It cannot distinguish I from J, does not retain spaces or punctuation, and filler X/Q may be indistinguishable from original letters. Review and edit the result.
How do I read Polybius coordinates?
Each digit pair identifies a letter by row and column. Select the same English or Russian grid when decoding; word spaces are not restored automatically.
Which alphabet does the Bacon cipher use?
The historical 24-letter table is used, with I/J and U/V sharing values. Decoding cannot tell which spelling was present in the original.
How do I decode a Scytale message?
Choose decode and enter the same number of columns used for encoding. The transposition rearranges graphemes without adding padding.
Are spaces and punctuation preserved?
Vigenere and Atbash leave them in place; Scytale transposes the entire text, including spaces and punctuation. Playfair, Polybius, and Bacon operate on letters/codes and do not retain the original formatting.
Can these methods protect sensitive information?
No. Classical ciphers have well-known structural weaknesses. They are for learning and puzzles, not passwords, secrets, or confidential messages.