Polybius tablets for encryption, illustration. Polybius tablets and squares were originally used in Ancient Greece to transmit messages via torches. It is a system used for encryption and telegraphy. It works by replacing each letter of the alphabet with a two digit number. | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Schroeder, Monica |
Taille de l’image : | 5638 px × 3100 px |
Model Release : | Non requis |
Property Release : | Non requis |
Restrictions : | - |