Thursday, May 09, 2019
Best peep
Counterexample to the stupid use of ciphering in previous item.
This description of a light-based telegraph credited to Aeneas is in a book about telegraphs published in 1808, twenty years before the first harnessing of electricity or magnetism for human purposes.
Each end had a water-clock, pointing to a list of sentences instead of a list of minutes. The sender flashed a torch and started his clock. The receiver started his clock when he saw the flash, and then flashed his torch to acknowledge receipt. As the pre-sync'd clocks dripped out water, the sender flashed again at the moment when the pointer hit the desired message. The receiver could then read the sentence from his own pointer.
This system had full security. Even if an enemy knew that a clock cipher was in use, the enemy wouldn't know the sentences on the board, and wouldn't know the drip speed or the spacing of the sentences. Both could be varied by a predetermined schedule if needed.
Serendipitous sidenote: Polistra's light-tower sending V for V-day is another type of clock cipher! I'm using it for plain old Morse, but it could be used like the Aeneas device.
Each end had a water-clock, pointing to a list of sentences instead of a list of minutes. The sender flashed a torch and started his clock. The receiver started his clock when he saw the flash, and then flashed his torch to acknowledge receipt. As the pre-sync'd clocks dripped out water, the sender flashed again at the moment when the pointer hit the desired message. The receiver could then read the sentence from his own pointer.
This system had full security. Even if an enemy knew that a clock cipher was in use, the enemy wouldn't know the sentences on the board, and wouldn't know the drip speed or the spacing of the sentences. Both could be varied by a predetermined schedule if needed.
Serendipitous sidenote: Polistra's light-tower sending V for V-day is another type of clock cipher! I'm using it for plain old Morse, but it could be used like the Aeneas device.Labels: Morsenet of Things
¶ 6:26 AM
