Four-Square Cipher Tutorials and Guides

Master the four-square cipher cipher with our comprehensive collection of tutorials, step-by-step guides, and practical examples.

Four-square
March 19, 2026
14 min read

Four-Square Cipher: Felix Delastelle's Digraph Encryption System Explained

A comprehensive guide to Felix Delastelle's Four-Square cipher, covering grid construction, step-by-step encryption and decryption, keyword selection, security analysis, and comparisons with Playfair and other digraph systems. Includes worked examples and historical context.

Try the Four-Square Cipher Tool

Put your knowledge into practice with our interactive four-square cipherencryption and decryption tool.

Try Four-Square Cipher Tool