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A comment on The NSA Furby Documents. Parent comment

Re:The NSA Furby Documents by sandworm101 on Tuesday January 23, 2024 @02:48PM (#39108720)
Because the signal transmitted over normal phones has to be encrypted. That encrypted signal will then be digitized/compressed by the standard phone line. Any artifacts in the phone line digitization might turn the encrypted signal into gibberish. Its like compressing a jpeg too many times. So you need an encryption method that isnt simple digitization. You need something that is encrypted but essentially sounds like human speech so that the digitization/compression process does not damage it.

https://gdmissionsystems.com/products/encryption/secure-voic...

https://www.cryptomuseum.com/crypto/gd/viper/

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Re:The NSA Furby Documents by WatchDog on Tuesday January 23, 2024 @07:02PM (#39111759)
We all used this kind of advanced technology to connect to the internet back in the 90s.
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Re:The NSA Furby Documents by sandworm101 on Tuesday January 23, 2024 @08:41PM (#39112569)
Not really. The phone lines were not compressed then.
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Re:The NSA Furby Documents by bux93 on Wednesday January 24, 2024 @07:53AM (#39116675)
They were, they got compressed with G.711 or G.722.

In fact, that's why your 56kbps modem would often fall back to 38.4kbps or 28k8, until the phone company installed a fancy new exchange that demodulated the 56kbps stream and didn't compress it. The 56kbps was also due to sampling limits/bandlimiters, on the same copper line you could also get a fully digital ISDN line that did 64kbps. (And if they remove all the filters and band limits, you can reach DSL speeds.)

There's nothing inherently special about voice-compression compared to any other kind of interference/distortion you can get on an analogue line.

Also, faxes still work?

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Re:The NSA Furby Documents by KMag on Wednesday January 24, 2024 @09:34AM (#39117756)
But that same re-compression happens with modem traffic. Your 56k modems deal with compression artifacts just fine, though sometimes dropping down to lower speeds.
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