- Monoalphabetic Ciphers
- Caesar Cipher
- Atbash Cipher
- Keyword Cipher
- Pigpen / Masonic Cipher
- Polybius Square
- Polyalphabetic Ciphers
- Vigenère Cipher
- Beaufort Cipher
- Autokey Cipher
- Running Key Cipher
- Polygraphic Ciphers
- Playfair Cipher
- Bifid Cipher
- Trifid Cipher
- Four-square cipher
- Transposition Ciphers
- Rail Fence
- Route Cipher
- Columnar Transposition
- Miscellaneous
- Book Cipher
- Beale Cipher
- Morse Code
- Tap Code
- One-time Pad
- Scytale
- Semaphore
- ASCII Code
- Steganography
- Techniques
- Frequency Analysis
- Books

# Codes and Ciphers
Codes and Ciphers
- Monoalphabetic Ciphers
- Caesar Cipher
- Atbash Cipher
- Keyword Cipher
- Pigpen / Masonic Cipher
- Polybius Square
- Polyalphabetic Ciphers
- Vigenère Cipher
- Beaufort Cipher
- Autokey Cipher
- Running Key Cipher
- Polygraphic Ciphers
- Playfair Cipher
- Bifid Cipher
- Trifid Cipher
- Four-square cipher
- Transposition Ciphers
- Rail Fence
- Route Cipher
- Columnar Transposition
- Miscellaneous
- Book Cipher
- Beale Cipher
- Morse Code
- Tap Code
- One-time Pad
- Scytale
- Semaphore
- ASCII Code
- Steganography
- Techniques
- Frequency Analysis
- Books

Polybius Square Cipher

- Monoalphabetic Ciphers
- Caesar Cipher
- Atbash Cipher
- Keyword Cipher
- Pigpen / Masonic Cipher
- Polybius Square
- Polyalphabetic Ciphers
- Vigenère Cipher
- Beaufort Cipher
- Autokey Cipher
- Running Key Cipher
- Polygraphic Ciphers
- Playfair Cipher
- Bifid Cipher
- Trifid Cipher
- Four-square cipher
- Transposition Ciphers
- Rail Fence
- Route Cipher
- Columnar Transposition
- Miscellaneous
- Book Cipher
- Beale Cipher
- Morse Code
- Tap Code
- One-time Pad
- Scytale
- Semaphore
- ASCII Code
- Steganography
- Techniques
- Frequency Analysis
- Books

A Polybius Square is a table that allows someone to translate letters into numbers. To give a small level of encryption, this table can be randomized and shared with the recipient. In order to fit the 26 letters of the alphabet into the 25 spots created by the table, the letters i and j are usually combined.

1 | 2 | 3 | 4 | 5 | |
---|---|---|---|---|---|

1 | A | B | C | D | E |

2 | F | G | H | I | K |

3 | L | M | N | O | P |

4 | Q | R | S | T | U |

5 | V | W | X | Y | Z |

To encipher a message you replace each letter with the row and column in which it appears. For example, D would be replaced with 14.

To decipher a message you find the letter that intersects the specified row and column.

**Example:**

Plaintext: This is a secret message

Ciphertext: 44232443 2443 11 431513421544 32154343112215

Ciphertext: 44232443 2443 11 431513421544 32154343112215

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