Four-Square Cipher
Encrypt and decrypt text using the Four-Square cipher. Uses two keyword-based 5x5 Polybius squares for digraph substitution, providing stronger encryption than simple substitution ciphers.
How to Use Four-Square Cipher
Enter two keywords to generate the cipher matrices, type your plaintext or ciphertext, select encrypt or decrypt mode, and click the button. The tool processes letter pairs using Four-Square substitution.
Step-by-Step Instructions
- Enter two keywords for the cipher matrices
- Type or paste text to encrypt/decrypt
- Select Encrypt or Decrypt mode
- Click the button and copy the result
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