User:Kopaka649/Historical Applications

Since antiquity, humans have strived for a method of secret communication. Some attempts resulted in great success, while others proved pathetic failures.

The Slave’s Head ~ 490 BC

Though more a method of hiding things than encryption, this tactic by the ancient Greeks represents one of the first attempts at private communication. A slave’s head is shaven then painfully tattoo with a plaintext message. Once the hair regrew, the servant was sent to the designated receiver who re-shaved to reveal a message. The slave had no clue what the message said.

Scytale Rod ~ 487 BC

The Spartan military carried out covert exchanges using a pair of cylindrical rods called scytales. A long narrow strip of parchment is wrapped around the pole, and a plaintext message written, each letter on a separate column. For instance, “HELP ME I AM UNDER ATTACK” translates to “HENTEIDTLAEAPMRCMUAK” when a rod of length 5 and circumference 4 is used. Once the message is written, the parchment is worn as a belt by a messenger, who delivers it to the recipient. Only when the parchment is wrapped around a cylinder of identical radius could the message be deciphered. Though top notch at the time, a modern computer can easily determine that the message is written at 4 letter intervals.