They were doing this with typewriters in Germany during the cold war, Mikko Hyppoonen talks about it in this Ted talk - https://www.ted.com/talks/mikko_hypponen

They were doing this with typewriters in Germany during the cold war, Mikko Hyppoonen talks about it in this Ted talk - https://www.ted.com/talks/mikko_hypponen_three_types_of_online_attack https://www.ted.com/talks/mikko_hypponen_three_types_of_onli...