Mariners' Museum Newport News Virginia Va. German Navy four rotor Enigma Cypher machine 1942 U boat : 無料・フリー素材/写真
Mariners' Museum Newport News Virginia Va. German Navy four rotor Enigma Cypher machine 1942 U boat / watts_photos
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
|---|---|
| 説明 | Mariners' Museum Newport News Virginia Va. German Navy four rotor Enigma Cypher machine 1942 U boatThe Enigma machines were a series of electro-mechanical rotor cipher machines developed and used in the early- to mid-twentieth century to protect commercial, diplomatic and military communication. Enigma was invented by the German engineer Arthur Scherbius at the end of World War To avoid merely implementing a simple (and easily breakable) substitution cipher, every key press caused one or more rotors to step by one twenty-sixth of a full rotation, before the electrical connections were made. This changed the substitution alphabet used for encryption, ensuring that the cryptographic substitution was different at each new rotor position, producing a more formidable polyalphabetic substitution cipher. The stepping mechanism varied slightly from model to model. The right-hand rotor stepped once with each keystroke, and other rotors stepped less frequently. |
| 撮影日 | 2016-08-21 14:18:14 |
| 撮影者 | watts_photos |
| タグ | |
| 撮影地 | |
| カメラ | Canon EOS M , Canon |
| 露出 | 0.033 sec (1/30) |
| 開放F値 | f/4.5 |
| 焦点距離 | 22 mm |