Polybius square. Diagram illustrating the principles of the Polybius square,a system used in encryption and telegraphy,first described by the ancient Greek scholar Polybius in around 200BC. It works by replacing each letter with a pair of grid co-ordinates. For example,S would become 43. Polybius conceived of this device as a way of transmitting messages optically with a pair of torches. For an artwork of the system in practice,see image V400/0090 | |
Lizenzart: | Lizenzpflichtig |
Credit: | Science Photo Library |
Bildgröße: | 4409 px × 4409 px |
Modell-Rechte: | nicht erforderlich |
Eigentums-Rechte: | nicht erforderlich |
Restrictions: | - |