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> Back in October 1944, Koenig had suggested a theoretical way of securing a telephone call by having the recipient of a call add noise to the signal and then s
by j2kun 10y ago
> Back in October 1944, Koenig had suggested a theoretical way of securing a telephone call by having the recipient of a call add noise to the signal and then subtract it afterward. Only Bob could subtract the noise, because only he knew what he had added in the first place. An eavesdropper, Eve, simply would not know how to modify the noise, because she wouldn’t have access to the noise that had been added to the phone conversation in the first place.
The scheme is called a one-time pad, and while it might be considered impractical, it was definitely used successfully. In fact Alan Turing apparently contributed to one such device: https://en.wikipedia.org/wiki/SIGSALY https://en.wikipedia.org/wiki/SIGSALY
- j2kun 10y agoInterestingly, according to Wikipedia the SIGSALY was in production before Koenig "invented" the technique. And according to the one-time pad page, one-time pad was first theoretically invented in 1882 by Frank Miller https://en.wikipedia.org/wiki/One-time_pad https://en.wikipedia.org/wiki/One-time_pad
- jgrahamc 10y agoYou should read the article and my comment above. This was not a one time pad as they was no distribution of a pad. Only one side added and removed the noise.
- j2kun 10y agoThe article you posted does not seem to contradict what I said, but rather support it. > The Project X method required courier distribution of noise tracks on phonograph records. Because the noise had to be as long as the speech it masked and each track could only be used once–it was the audio equivalent of a Vernam cipher or a one-time pad–the system was exceedingly cumbersome.
- jgrahamc 10y agoYou don't appear to have read it.