A 1983 review of this remarkable system for the Institute of Electrical and Electronic Engineers (IEEE) attributes no fewer than eight "firsts" to SIGSALY. They are as follows:
1) The first realization of enciphered telephony
2) The first quantized speech transmission
3) The first transmission of speech by Pulse Code Modulation (PCM)
4) The first use of companded PCM
5) The first examples of multilevel Frequency Shift Keying (FSK)
6) The first useful realization of speech bandwidth compression
7) The first use of FSK - FDM (Frequency Shift Keying-Frequency Division Multiplex) as a viable transmission method over a fading medium
8) The first use of a multilevel "eye pattern" to adjust the sampling intervals (a new, and important, instrumentation technique)
> a pair of vinyl phonograph records, each containing identical-but-random noise.
> These were the (single-use) keys to the encryption and decryption process.
> Then they set their identical records spinning at the exact same moment. On each end, the voices of these two world leaders are threaded through the SIGSALY terminal, mixed with a layer of noise, sent across the ocean via shortwave radio, then re-synthesized in a reverse process.
> Anyone attempting to listen in on the calls would just hear a buzzing sound, which is how the system earned one of its nicknames: “The Green Hornet,”
> At the end of each conversation, the records were destroyed to protect against potential future decryption.
I wonder if with todays tech we could decrypt this. This sounds really close to a one-time pad (if the conversation was kept shorter than each record) so .. probably not? Unless their random noise wasn't as random, or if the mixing of random + voice would leave other tell-tale signs?
funnymunny 5 minutes ago [-]
For anyone interested in this stuff - “Battle of Wits” is a great book about cryptanalysis in WW2.
saghm 32 minutes ago [-]
> Each terminal cost $1 million (at 1943 values) and weighed more than 50,000 kg (50 tonnes). The first one was housed in the Pentagon, with an extension to the White House. A further 11 terminals were installed at different sites around the world, including one in the sub-sub-basement of Selfridges department store in central London
I've learned that I tend to underestimate how large inflation is for historical values, so I looked this up. $1 million in 1943 is apparently just under $19.5 billion today, which means the full set cost $234 billion. I'm not sure if the US foot the bill for all of them or not, but to make it more concrete, 44 of these would have cost more than entire budget for the Department of Defense for this year.
leonidasrup 9 minutes ago [-]
For comparison, the unit cost of Boeing B-29 Superfortress (manufactured 1943–1946) was $639,188. In total 3,970 B-29s were build.
1 mil seems like an arbitrary or at least rounded number, and also it's not like you could get one on the market, so maybe it actually didn't cost a million
gedy 10 minutes ago [-]
No, inflation it's $19,476,300 in today's dollars. 19 million not billion.
scrlk 22 minutes ago [-]
You're an order of magnitude off: $1M in 1943 is ~$19.5M today.
I know this is a bit offtopic, but shouldn't the title say "the President of the United States," since 1) Churchill is UK's Prime Minister, and Roosevelt is not his President and 2) the publication on which this article appears is from the UK?
jhbadger 54 minutes ago [-]
Even the original UK article just says "the President". Things may change as the US may not play the leading role in this century as it did the last, but despite many countries having presidents (although not the UK), it is still understood that "the President" means POTUS.
saghm 55 minutes ago [-]
If the article itself (seemingly from the UK, as you point out) is inclined to assume that it's fine to describe it this way, I don't see why those of us from the rest of the world (which I'm inferring from your username is a group you're a part of) should object.
2 hours ago [-]
dfxm12 13 minutes ago [-]
I think historic context provides enough clarity for readers of the website of the imperial war museum.
I also think the headline as is would be good enough even for people who might not have learned about ww2 yet. A headline is not meant to be a complete summary after all...
hydrogen7800 1 hours ago [-]
There was a 99% invisible episode on this [0]. I recall there being some good audio examples.
Does anyone know how they synchronized the time? Was a radio signal fast enough?
AlexCoventry 2 hours ago [-]
IIRC from Prof: Alan Turing Decoded, Turing was sent to the US to work on this for a while, but wasn't able to contribute much, because the Americans didn't really trust him.
excannuk 3 hours ago [-]
[dead]
kachnuv_ocasek 3 hours ago [-]
* US president
Rendered at 20:40:16 GMT+0000 (Coordinated Universal Time) with Vercel.
1) The first realization of enciphered telephony
2) The first quantized speech transmission
3) The first transmission of speech by Pulse Code Modulation (PCM)
4) The first use of companded PCM
5) The first examples of multilevel Frequency Shift Keying (FSK)
6) The first useful realization of speech bandwidth compression
7) The first use of FSK - FDM (Frequency Shift Keying-Frequency Division Multiplex) as a viable transmission method over a fading medium
8) The first use of a multilevel "eye pattern" to adjust the sampling intervals (a new, and important, instrumentation technique)
From https://www.jproc.ca/crypto/sigsaly1.html
I think that the relevant patents remained classified until 1975.
> Then they set their identical records spinning at the exact same moment. On each end, the voices of these two world leaders are threaded through the SIGSALY terminal, mixed with a layer of noise, sent across the ocean via shortwave radio, then re-synthesized in a reverse process.
> Anyone attempting to listen in on the calls would just hear a buzzing sound, which is how the system earned one of its nicknames: “The Green Hornet,”
> At the end of each conversation, the records were destroyed to protect against potential future decryption.
I wonder if with todays tech we could decrypt this. This sounds really close to a one-time pad (if the conversation was kept shorter than each record) so .. probably not? Unless their random noise wasn't as random, or if the mixing of random + voice would leave other tell-tale signs?
I've learned that I tend to underestimate how large inflation is for historical values, so I looked this up. $1 million in 1943 is apparently just under $19.5 billion today, which means the full set cost $234 billion. I'm not sure if the US foot the bill for all of them or not, but to make it more concrete, 44 of these would have cost more than entire budget for the Department of Defense for this year.
https://en.wikipedia.org/wiki/B-29
https://www.bls.gov/data/inflation_calculator.htm
I also think the headline as is would be good enough even for people who might not have learned about ww2 yet. A headline is not meant to be a complete summary after all...
[0] https://99percentinvisible.org/episode/vox-ex-machina/
There is an illustration for the encryption process in Appendix B here: https://www.nsa.gov/portals/75/documents/about/cryptologic-h...