Invention by Félix Delastelle
French cryptographer Félix Delastelle invents the Four Square Cipher, aiming to improve upon existing polygraphic ciphers like the Playfair cipher.
1902
1906
Publication in "Traité Élémentaire de Cryptographie"
The Four Square Cipher is formally introduced to the public in Delastelle's book "Traité Élémentaire de Cryptographie," which details various cryptographic methods.
1914
Use in World War I
The Four Square Cipher sees limited use during World War I, primarily by French military units seeking a secure method for field communication.
1920
Adoption by Cryptographic Enthusiasts
Amateur cryptographers and puzzle enthusiasts begin to explore and use the Four Square Cipher in various cryptographic challenges and publications.
1939
Increased Interest During World War II
With the outbreak of World War II, there is a renewed interest in classical ciphers, including the Four Square Cipher, as nations seek reliable encryption methods.
1949
Featured in Cryptographic Literature
The Four Square Cipher is discussed in several cryptographic literature pieces, highlighting its structure and application in secure communication.
1963
Inclusion in Cryptography Textbooks
The Four Square Cipher is included in modern cryptography textbooks as an example of historical encryption methods, illustrating its principles and usage.
1977
Analysis by Cryptographic Historians
Cryptographic historians analyze the Four Square Cipher, examining its effectiveness and historical significance in the development of encryption techniques.
1984
Introduction in Academic Courses
The Four Square Cipher is introduced in academic courses on cryptography, allowing students to study and understand classical encryption methods.
1995
Integration into Cryptographic Software
The Four Square Cipher is integrated into cryptographic software tools for educational purposes, enabling users to experiment with the cipher digitally.
2001
Online Cryptographic Communities
Online cryptographic communities begin to explore and discuss the Four Square Cipher, sharing insights and challenges related to its use.
2008
Cryptographic Competitions
The Four Square Cipher is featured in cryptographic competitions, challenging participants to encrypt and decrypt messages using the cipher.
2013
Educational Workshops
Educational workshops on classical cryptography include the Four Square Cipher, teaching participants about its history and application.
2017
Publication in Cryptographic Journals
The Four Square Cipher is discussed in cryptographic journals, with articles analyzing its structure and effectiveness in modern contexts.
2021
Inclusion in Cryptographic Exhibits
The Four Square Cipher is included in exhibits on the history of cryptography, showcasing its role in the development of encryption methods.
2024
Continued Study and Application
The Four Square Cipher continues to be studied and applied in educational settings, demonstrating the enduring relevance of classical encryption techniques.
