The Art of Decryption in the 17th century

This handbook describes the decryption of simple and composite French and Spanish ciphers in the 17th century and shows the applied methods and examples.

Translated from the original French book: L'art de deschiffrer. Traité de déchiffrement du XVIIe siècle de la Secrétairerie d'Etat et de Guerre Espagnole, 1668-1714. Written In 1967 by J.P. Devos, H. Seligman. Université De Louvain.