Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Receiving unintentional voice transmissions from GPS satellites

rtl-sdr.com

Post reply on HN
Print view View original

41–50 of 93 posts

Re: Receiving unintentional voice transmissions from GPS satellites

#41

Post by niij »

withinboredom wrote: post #30
charcircuit wrote: post #24

Earlier quoted context omitted.

You are ignoring HTTPS allows people half a world awaywo exchange keys with a server and prevents other people follow interfering other than DoS attacks. >As we all learned in WWII, a code is better than encryption when you need complex PKI to achieve encryption I was never in WWII and I'm not sure what you mean by code as typically that's just encryption but less formalized.

[flagged]

I'd take it easy with the name calling. Your replies in this thread have shown a pretty fundamental misunderstanding of the OSI model, PKI, and encryption in general.

Re: Receiving unintentional voice transmissions from GPS satellites

#42

Post by kelnos »

krisoft wrote: post #36
withinboredom wrote: post #28

Earlier quoted context omitted.

You still need to exchange keys. You can't get around that. Otherwise, how do I know the public key you sent me over the radio is YOUR public key and not someone else with a more powerful radio?

By having the key signed by someone who you trust. Which in a military typically means the central command.

Sure, but then you need the central command's public key in order to verify that signature. How do you get that?

Ultimately it boils down to you needing to bootstrap your web/chain of trust somehow. In a military it might be easier; radios would be distributed to field troops with the needed trusted keys already present.

But more "public" radio? We don't have a sort of "radio CA", and there are no radios that know how to deal with such a thing. I suppose we could reuse the TLS CAs, though, and build SDRs to use it, which wouldn't rely on any particular hardware. But the point is that this just isn't set up at all.

Re: Receiving unintentional voice transmissions from GPS satellites

#43

Post by Y_Y »

stevezsa8 wrote: post #40
withinboredom wrote: post #19

Earlier quoted context omitted.

That’s because there isn’t a point. In order for encryption to work, you need to exchange keys at some point. Doing that half a world away is rather pointless. Doing it over the air, how do I know Alice won’t intercept and broadcast her keys louder than me? Or just interfere and prevent me from sending keys? As we all learned in WWII, a code is better than encryption when you need complex PKI to achieve encryption. I…

I watched some documentary where the US were monitoring enemy communications but didn't know what a specific code word was referring to. If I recall correctly, the US staged a fake transmission that one of their islands had some issue or other... and suddenly they picked up enemy broadcast with the code word in question. So then the US knew what the code word referred to.

AF meant Midway

https://www.history.navy.mil/content/dam/museums/nmas/educat...

It's very easy to look these things up.

Re: Receiving unintentional voice transmissions from GPS satellites

#44

Post by doctor_eval »

jcrawfordor wrote: post #16
dweekly wrote: post #9

Earlier quoted context omitted.

What is your basis for a claim that 121.5 (guard) is unmonitored? As a pilot I can say that claim is false - guard is very actively monitored everywhere in the United States. Were you referring to some other locations?

COSPAS-SARSAT no longer monitors 121.5, for various reasons, so no satellite systems regularly monitor 121.5. This means that 121.5-only ELTs are obsolete, and prohibited for installation by the FAA since 2018. Modern ELTs are COSPAS-SARSAT transponders like EPIRBs and PLBs with only minor aviation-specific features. ATC does still monitor 121.5, but that's with an eye towards voice transmissions, not radio beacon ac…

I had to look this up. Wow!

https://en.m.wikipedia.org/wiki/International_Cospas-Sarsat_...

> The International Cospas-Sarsat Programme is a satellite-aided search and rescue (SAR) initiative. It is organized as a treaty-based, nonprofit, intergovernmental, humanitarian cooperative of 45 nations and agencies (see infobox). It is dedicated to detecting and locating emergency locator radio beacons activated by persons, aircraft or vessels in distress, and forwarding this alert information to authorities that can take action for rescue. Member countries operate a constellation of around 66 satellites orbiting the Earth which carry radio receivers capable of locating an emergency beacon anywhere on Earth transmitting on the Cospas-Sarsat frequency of 406 MHz.

Re: Receiving unintentional voice transmissions from GPS satellites

#45

Post by toast0 »

mananaysiempre wrote: post #32
ajsnigrutin wrote: post #29

Earlier quoted context omitted.

Most of them are pretty secure, a few really old or intentionally open (ham radio) are not, but the rest, are (wifi, 5g, ...)

Does 5G finally use some sort of viable cryptosystem? 3G and below are hopeless and IIUC LTE is theoretically possible to secure but in practice the implementations suck.

IIRC, LTE is mutually verified encryption. The SIM contains a private key for the subscriber and a public key for the network. I'd expect 5G to also have that.

Re: Receiving unintentional voice transmissions from GPS satellites

#46

Post by aleph_minus_one »

charcircuit wrote: post #10
acaloiar wrote: post #8

Few things evoke feelings of the early internet like intercepting unencrypted communications in the wild with off the shelf hardware and software. It's some how comforting to realize this is still possible today.

Considering how much progress that has been made in encrypting internet traffic radio seems painfully slow in evolving to be more secure. Edit: specifically radio protocols not carrying internet traffic

> Considering how much progress that has been made in encrypting internet traffic radio seems painfully slow in evolving to be more secure.

An important reason that I see is because (at least in Germany, I guess worldwide) ham radio operators are not allowed to encrypt their traffic. Commercial companies are a lot more conservative concerning encryption than "hacker people".

Re: Receiving unintentional voice transmissions from GPS satellites

#47

Post by SAI_Peregrinus »

rootw0rm wrote: post #34
charcircuit wrote: post #24

Earlier quoted context omitted.

You are ignoring HTTPS allows people half a world awaywo exchange keys with a server and prevents other people follow interfering other than DoS attacks. >As we all learned in WWII, a code is better than encryption when you need complex PKI to achieve encryption I was never in WWII and I'm not sure what you mean by code as typically that's just encryption but less formalized.

Referring to Navajo code talkers I assume... https://en.m.wikipedia.org/wiki/Code_talker

Which is especially funny, because their communications were encrypted after they encoded them into Navajo.

Re: Receiving unintentional voice transmissions from GPS satellites

#48

Post by _whiteCaps_ »

If anyone is interested in satellites, check out your options for amateur radio licensing in your country. The ISS has a repeater that even the most basic license holder is able to use. It's using VHF/UHF frequencies, and a low power 5W radio is enough to work it.

Occasionally the astronauts will get on the radio as well and chat with you! I haven't been lucky enough to do that yet. But I have heard them talking when passing overhead.

https://amsat.org has more information.

Re: Receiving unintentional voice transmissions from GPS satellites

#49

Post by dweekly »

jcrawfordor wrote: post #16
dweekly wrote: post #9

Earlier quoted context omitted.

What is your basis for a claim that 121.5 (guard) is unmonitored? As a pilot I can say that claim is false - guard is very actively monitored everywhere in the United States. Were you referring to some other locations?

COSPAS-SARSAT no longer monitors 121.5, for various reasons, so no satellite systems regularly monitor 121.5. This means that 121.5-only ELTs are obsolete, and prohibited for installation by the FAA since 2018. Modern ELTs are COSPAS-SARSAT transponders like EPIRBs and PLBs with only minor aviation-specific features. ATC does still monitor 121.5, but that's with an eye towards voice transmissions, not radio beacon ac…

Helpful additional data on COSPAS-SARSAT, thank you! I didn't realize ELTs that only output on 121.5 were no longer a thing.

That said, the claim I was responding to was "121.5 and 243 MHz are no longer officially monitored for voice distress signals", which is pretty obviously false.

Re: Receiving unintentional voice transmissions from GPS satellites

#50

Post by NoZebra120vClip »

My father is a radio lover, a DXer, and sometimes nearly contemplated a ham license. So I grew up with him listening to shortwave and other bands, he explained all the concepts, WWV would be on for two hours at a time (you could literally count every minute). Another fixture was the police/fire scanner that would be on most evenings, especially when we heard sirens. Dad put up a nice rotary Yagi VHF/UHF tower for the television set, so we would play with the rotary control to dial in better reception, whatever channel we watched.

So then I found channel 70-83 on the TV, and discovered that AMPS cell phone conversations would drift in and out on those channels if I just let them sit for long enough. So Dad strictly enjoined me not to reveal what I learned from those conversations. And I lost interest, because not much interesting was being said, and the broadcasts were partial, probably because the typical use of AMPS was for car phones, not people walking by on the sidewalk.

Post reply on HN