- Monoalphabetic
- Caesar Cipher
- Atbash Cipher
- Keyword Cipher
- Pigpen / Masonic Cipher
- Polybius Square
- Polyalphabetic
- Vigenère Cipher
- Beaufort Cipher
- Autokey Cipher
- Running Key Cipher
- Polygraphic
- Playfair Cipher
- Bifid Cipher
- Trifid Cipher
- Four-square cipher
- Transposition
- 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
- Caesar Cipher
- Atbash Cipher
- Keyword Cipher
- Pigpen / Masonic Cipher
- Polybius Square
- Polyalphabetic
- Vigenère Cipher
- Beaufort Cipher
- Autokey Cipher
- Running Key Cipher
- Polygraphic
- Playfair Cipher
- Bifid Cipher
- Trifid Cipher
- Four-square cipher
- Transposition
- 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
- Monoalphabetic
- Caesar Cipher
- Atbash Cipher
- Keyword Cipher
- Pigpen / Masonic Cipher
- Polybius Square
- Polyalphabetic
- Vigenère Cipher
- Beaufort Cipher
- Autokey Cipher
- Running Key Cipher
- Polygraphic
- Playfair Cipher
- Bifid Cipher
- Trifid Cipher
- Four-square cipher
- Transposition
- 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
Keyword Cipher
The Keyword cipher is identical to the Caesar Cipher with the exception that the substitution alphabet used can be represented with a keyword.
To create a substitution alphabet from a keyword, you first write down the alphabet. Below this you write down the keyword (omitting duplicate letters) followed by the remaining unused letters of the alphabet.
ABCDEFGHIJKLMNOPQRSTUVWXYZ
KEYWORDABCFGHIJLMNPQSTUVXZ
KEYWORDABCFGHIJLMNPQSTUVXZ
To encipher a plaintext message, you convert all letters from the top row to their correspondng letter on the bottom row (A to K, B to E, etc).
These types of simple substitution ciphers can be easily cracked by using frequency analysis and some educated guessing.
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