The Pigpen Cipher (also known as the Masonic Cipher, Freemason's Cipher, or Tic-Tac-Toe Cipher) is a geometric substitution cipher that replaces each letter of the alphabet with a unique symbol. These symbols are derived from the segments of a grid — resembling the pens where pigs are kept, hence the name "pigpen." It was widely used by the Freemasons in the 18th century for secret communications and record-keeping. Today, it remains a popular educational tool for teaching basic cryptography concepts.

The cipher uses four grids to encode 26 letters:

Grid 1 (no dot): A 3×3 grid holds letters A through I. Each letter's symbol is the shape of its cell's walls. Corner cells form L-shapes, edge-middle cells form U-shapes, and the center cell forms a small square.

Grid 2 (with dot): Same 3×3 layout for letters J through R, but with a dot in the center to distinguish them from Grid 1.

Grid 3 (X-shape, no dot): An X-shaped grid (two diagonal lines forming four V-shaped regions) holds letters S through V.

Grid 4 (X-shape, with dot): Same X layout for letters W through Z, with a dot added for differentiation.

No, the Pigpen Cipher is a classic substitution cipher and offers no real security by modern standards. It can be easily cracked using frequency analysis or by recognizing the distinctive geometric symbols. It is primarily used today for educational purposes, puzzles, escape rooms, treasure hunts, and recreational cryptography. For secure communication, use modern encryption algorithms like AES or RSA.

Several variations exist:
• Standard Masonic: Uses the 3×3 grids and X-grids as implemented here (A-I, J-R, S-V, W-Z).
• Rosicrucian variant: Assigns letters differently within the grids.
• Extended versions: Some variants include additional grids for numbers or punctuation.
• Mirror variants: The grid orientation may be rotated or mirrored, changing which shape corresponds to which letter.
• Keyword variants: A keyword is used to rearrange letter assignments, adding a layer of complexity.

The name "Pigpen" comes from the resemblance of the grid-based symbols to the pens or enclosures used to keep pigs on a farm. The segmented squares look like small fenced areas viewed from above. The cipher is also known as the "Masonic Cipher" due to its historical association with Freemasonry, or the "Tic-Tac-Toe Cipher" because the 3×3 grids resemble a tic-tac-toe board.

Yes! Use the Decode mode of this tool. Simply click the symbols that match what you see in your message, and the decoded text will appear below. If the symbols don't match our reference chart, the message may use a variant of the cipher — try rotating the grid assignments or checking if a keyword was used to shuffle the letters.

Grid 2 symbols (letters J–R) look exactly like Grid 1 symbols (A–I) but include a small dot in the center of the cell. For example, the symbol for A (top-left corner of Grid 1) is an L-shape with no dot, while J (same position in Grid 2) is the same L-shape but with a dot inside. Similarly, Grid 4 symbols (W–Z) have a dot, distinguishing them from Grid 3 (S–V).