How did spies spy codes?

Answer 1

There are all different types of ciphers and codes used in Intelligence- and to keep messages secret except to the proper audience- readership. Invisible Ink is not strictly speaking a code or cipher but is related. Like Photography, it has to be developed- Sgt. Carter, who was a chemist in civil life- did this job in Hogan"s Heroes ( not the Marine Sergeant- but an Army man). Larry Hovis did this job. Ivan Dixon was Kinchelow- the Black, (what else) Radio operator ( this job seemed to always involve Negro actors and actresses)- Radiotelegraphy might involve super-enciphered messages. the message traffic in Morse Code to begin with- might be condensed to ciphers like AGDV 4X which would be meaningles even if decoded by the man in the street-unless he had a code book up to date. ( they were changed monthly- in the German armed forces, and this was using machine ciphers,. they were mainy based on five letter ciphers- AGDVY -for example- this might mean- attack alternate target if plans fail. late in the war the one-time tape was developed- which if properly secured- no peaking- is a nearly invulnerable cipher as no element is repeated which would aid enemy codebreakers- the drawback is it is used only once- it cannot be used- say over the phone or where a developed two-way message traffic is the need- as in walkie talkies. again Odhu NTTinggo ( so-called Navaho Cipher- it is a transposition- and means- Good Hunting! sage advice on the crypto front- read Kahn"s bookd ( David Kahn, the best-known popular writer on this subject.