Nihilist Cipher Decoder

How to Use the Nihilist Cipher Decoder

1. Enter your encrypted message in the "Ciphertext" field
2. Enter the keyword used for the Polybius square (if known)
3. Enter the second keyword used for encryption (if known)
4. Click "Decrypt" to decode your message
5. View the decrypted result in the output section

About the Nihilist Cipher

The Nihilist cipher is a symmetric encryption cipher that uses a Polybius square and a keyword. It was used by Russian Nihilists in the 19th century, hence its name. The cipher involves two steps:

1. First, a Polybius square is created using a keyword (or the standard alphabet)
2. Then, each letter of the plaintext is converted to its coordinates in the square
3. Another keyword is used to generate a sequence of numbers that are added to the plaintext numbers

To decrypt, you need to know both keywords or be able to reconstruct the Polybius square.