SIGSALY: Churchill's top secret hotline to the president
iwm.org.uk75 points by stmw 4 days ago
75 points by stmw 4 days 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.
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
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)
From https://www.jproc.ca/crypto/sigsaly1.html
I think that the relevant patents remained classified until 1975.
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?
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.
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.
There was a 99% invisible episode on this [0]. I recall there being some good audio examples.
A great example of a one-time pad!
There is an illustration for the encryption process in Appendix B here: https://www.nsa.gov/portals/75/documents/about/cryptologic-h...
Also, worth reading about is Turing's Delilah speech encryption system: https://spectrum.ieee.org/alan-turings-delilah
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.
[dead]
* US president