5 ms·

SIGSALY – Secure Speech System Used in WWII by the Allies

56 points by notlukesky 7y ago

tasty_freeze 7y ago
A site with far more information about it: https://www.cryptomuseum.com/crypto/usa/sigsaly/index.htm https://www.cryptomuseum.com/crypto/usa/sigsaly/index.htm
- dang 7y ago
  Ok, changed to that from https://en.wikipedia.org/wiki/SIGSALY https://en.wikipedia.org/wiki/SIGSALY. Thanks! Edit: there's also https://www.nsa.gov/about/cryptologic-heritage/historical-figures-publications/publications/wwii/sigsaly-story/ https://www.nsa.gov/about/cryptologic-heritage/historical-fi..., via https://hn.algolia.com/?sort=byDate&dateRange=all&type=story&storyText=false&prefix=false&page=0&query=sigsaly https://hn.algolia.com/?sort=byDate&dateRange=all&type=story....
modoc 7y ago
Very cool to read all the details beyond the one-time-pad records described in Cryptonomicon!
- BuildTheRobots 7y ago
  Solitaire Cyphers are the one that stuck with me from Cryptonomicon. iirc, there's supposed to be enough combinations in a shuffled deck of cards that every time anyone shuffles a deck, it should be a unique ordering. https://www.schneier.com/academic/solitaire/ https://www.schneier.com/academic/solitaire/
- satori99 7y ago
  This technology (SIGSALY) also features in Cryptonomicon. Lawrence Waterhouse uses it while he stationed in Brisbane to talk chat to Turing on the other other side of the planet. It is not a major plot device, but it is used.
Ken_Adler 7y ago
A great book to read on this topic is 'How To Wreck A Nice Beach" https://www.amazon.com/How-Wreck-Nice-Beach-Vocoder/dp/1612190928 https://www.amazon.com/How-Wreck-Nice-Beach-Vocoder/dp/16121...
ganoushoreilly 7y ago
If you're ever in the D.C / Maryland area, Fort Meade has a pretty cool museum with all of these on display. https://www.nsa.gov/about/cryptologic-heritage/museum/ https://www.nsa.gov/about/cryptologic-heritage/museum/
madengr 7y ago
Interesting that they added the code (random noise) to the data rather than multiply (XOR). I assume this was safe to do since averaging won’t recover much signal when the signal rate and code rate are the same. Also interesting that the basement in that department store went down 200 feet. Was this to get a good foundation? The link does not say.
- Aloha 7y ago
  Isn't an add much cheaper than a multiply?
  - madengr 7y ago
    Sure, but typically bit-wise multiply by XOR is used, at least with spread spectrum and many forward error correction.
    - kps 7y ago
      They weren't using base 2.
    - ncmncm 7y ago
      Using base-6 signaling, modulo addition per digit position is a close equivalent to XOR for binary.
- Someone 7y ago
  ”Also interesting that the basement in that department store went down 200 feet. Was this to get a good foundation?” It’s not as much as “below Selfridge’s” as “effectively in the cabinet war rooms”. https://en.wikipedia.org/wiki/Military_citadels_under_London#Cabinet_War_Rooms https://en.wikipedia.org/wiki/Military_citadels_under_London...: ”There was a telephone room down the corridor that provided a direct line to the White House in Washington, DC, via a special scrambler in an annexe basement of Selfridges department store.”
kristaps 7y ago
Would really love to hear what the final output sounded like. Some light googling found no recordings, did anyone else have more luck?
- joezydeco 7y ago
  The 99%PI podcast does a little simulation: https://99percentinvisible.org/episode/vox-ex-machina/ https://99percentinvisible.org/episode/vox-ex-machina/ Scroll down "Below you can hear an example of what a SIGSALY communication would’ve sounded like"
Animats 7y ago
More technical information: [1] This gives a sense of how much 1940s equipment it took to do something every mobile phone does today. This is another device from the "if only we had memory" era of early computing. IBM had a digital vacuum tube multiplier before WWII, and semi-programmable electromechanical computing machines. Good memory devices were in the future. The 1940s and early 1950s saw quite a collection of strange memory devices, all big, expensive, or slow. Often all three. SIGSALY had massive synchronized phonograph turntables as key storage. Memory took quite a while to get cheap. Core memory was still around a million dollars a megabyte in 1970. Memory didn't get cheap until the 1990s. [1] https://www.nsa.gov/about/cryptologic-heritage/historical-figures-publications/publications/wwii/sigsaly-start-digital/ https://www.nsa.gov/about/cryptologic-heritage/historical-fi...
belltyler 7y ago
First learned about this on a highly-recommended episode of 99% Invisible: https://99percentinvisible.org/episode/vox-ex-machina/ https://99percentinvisible.org/episode/vox-ex-machina/
meatsock 7y ago
as a record collector, the idea that top secret military phonographs filled with white noise may have once existed sure is exiting. can there possibly be any rarer record than one that required it's own destruction after use?

56 points by notlukesky 7y ago

A site with far more information about it: https://www.cryptomuseum.com/crypto/usa/sigsaly/index.htm https://www.cryptomuseum.com/crypto/usa/sigsaly/index.htm

dang 7y ago
Ok, changed to that from https://en.wikipedia.org/wiki/SIGSALY https://en.wikipedia.org/wiki/SIGSALY. Thanks! Edit: there's also https://www.nsa.gov/about/cryptologic-heritage/historical-figures-publications/publications/wwii/sigsaly-story/ https://www.nsa.gov/about/cryptologic-heritage/historical-fi..., via https://hn.algolia.com/?sort=byDate&dateRange=all&type=story&storyText=false&prefix=false&page=0&query=sigsaly https://hn.algolia.com/?sort=byDate&dateRange=all&type=story....

modoc 7y ago

Very cool to read all the details beyond the one-time-pad records described in Cryptonomicon!

BuildTheRobots 7y ago
Solitaire Cyphers are the one that stuck with me from Cryptonomicon. iirc, there's supposed to be enough combinations in a shuffled deck of cards that every time anyone shuffles a deck, it should be a unique ordering. https://www.schneier.com/academic/solitaire/ https://www.schneier.com/academic/solitaire/
satori99 7y ago
This technology (SIGSALY) also features in Cryptonomicon. Lawrence Waterhouse uses it while he stationed in Brisbane to talk chat to Turing on the other other side of the planet. It is not a major plot device, but it is used.

Ken_Adler 7y ago

A great book to read on this topic is 'How To Wreck A Nice Beach" https://www.amazon.com/How-Wreck-Nice-Beach-Vocoder/dp/1612190928 https://www.amazon.com/How-Wreck-Nice-Beach-Vocoder/dp/16121...

ganoushoreilly 7y ago

If you're ever in the D.C / Maryland area, Fort Meade has a pretty cool museum with all of these on display. https://www.nsa.gov/about/cryptologic-heritage/museum/ https://www.nsa.gov/about/cryptologic-heritage/museum/

madengr 7y ago

Interesting that they added the code (random noise) to the data rather than multiply (XOR). I assume this was safe to do since averaging won’t recover much signal when the signal rate and code rate are the same. Also interesting that the basement in that department store went down 200 feet. Was this to get a good foundation? The link does not say.

Aloha 7y ago
Isn't an add much cheaper than a multiply?
- madengr 7y ago
  Sure, but typically bit-wise multiply by XOR is used, at least with spread spectrum and many forward error correction.
  - kps 7y ago
    They weren't using base 2.
  - ncmncm 7y ago
    Using base-6 signaling, modulo addition per digit position is a close equivalent to XOR for binary.
Someone 7y ago
”Also interesting that the basement in that department store went down 200 feet. Was this to get a good foundation?” It’s not as much as “below Selfridge’s” as “effectively in the cabinet war rooms”. https://en.wikipedia.org/wiki/Military_citadels_under_London#Cabinet_War_Rooms https://en.wikipedia.org/wiki/Military_citadels_under_London...: ”There was a telephone room down the corridor that provided a direct line to the White House in Washington, DC, via a special scrambler in an annexe basement of Selfridges department store.”

kristaps 7y ago

Would really love to hear what the final output sounded like. Some light googling found no recordings, did anyone else have more luck?

joezydeco 7y ago
The 99%PI podcast does a little simulation: https://99percentinvisible.org/episode/vox-ex-machina/ https://99percentinvisible.org/episode/vox-ex-machina/ Scroll down "Below you can hear an example of what a SIGSALY communication would’ve sounded like"

Animats 7y ago

More technical information: [1] This gives a sense of how much 1940s equipment it took to do something every mobile phone does today. This is another device from the "if only we had memory" era of early computing. IBM had a digital vacuum tube multiplier before WWII, and semi-programmable electromechanical computing machines. Good memory devices were in the future. The 1940s and early 1950s saw quite a collection of strange memory devices, all big, expensive, or slow. Often all three. SIGSALY had massive synchronized phonograph turntables as key storage. Memory took quite a while to get cheap. Core memory was still around a million dollars a megabyte in 1970. Memory didn't get cheap until the 1990s. [1] https://www.nsa.gov/about/cryptologic-heritage/historical-figures-publications/publications/wwii/sigsaly-start-digital/ https://www.nsa.gov/about/cryptologic-heritage/historical-fi...

belltyler 7y ago

First learned about this on a highly-recommended episode of 99% Invisible: https://99percentinvisible.org/episode/vox-ex-machina/ https://99percentinvisible.org/episode/vox-ex-machina/

meatsock 7y ago

as a record collector, the idea that top secret military phonographs filled with white noise may have once existed sure is exiting. can there possibly be any rarer record than one that required it's own destruction after use?