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Reverse engineering a mysterious UDP stream in my hotel (2016)

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Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#101

Post by inferiorhuman »

op00to wrote: post #91
inferiorhuman wrote: post #89

Earlier quoted context omitted.

Sonic used to offer mbone connectivity (including BBC channels) back when they were an internet service provider and not a web provider. It was pretty nifty but never very user friendly to set up.

When I worked at a core i2 .edu site, we had all the "hd" mbone tv streams. It was pretty wild considering HD was a "new" thing! Thanks for reminding me of that wonderful time!

Wikipedia had this quote from Mick Jagger:

  I wanna say a special welcome to everyone that's, uh, climbed into the
  Internet tonight and, uh, has got into the M-bone. And I hope it doesn't
  all collapse.
What a time to be alive.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#102

Post by thfuran »

anyfoo wrote: post #80
mike_d wrote: post #77

Earlier quoted context omitted.

Remember that networks introduce latency. It might be tiny but the human ear can detect speakers being _slightly_ off. For example you wouldn't want a wifi speaker in an elevator using a repeater at the top of the shaft trying to match up to a hardwired speaker in a ground floor vestibule.

You can use NTP to get the devices' clocks synced up to much better than necessary tolerance, and play back accordingly. And then you "just" have the same problems that you have with purely electrically connected, analogue speakers (which are effectively 100% in sync in terms of receiving the signal): Sound is relatively slow, and so the audio from a speaker that is far away will reach you later than the nearby speak…

You just need to take a cue from wifi and use beam forming to send separately synced audio to each person.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#103

Post by hot_gril »

anyfoo wrote: post #100
hot_gril wrote: post #94

Earlier quoted context omitted.

> I'm honestly not convinced I read a less "overengineered" solution so far... Prerecorded music on an MP3 player sounds like the one simpler solution, though it wouldn't put the elevators in sync with each other or let you control it remotely.

Yes, but if you want to do even as much as not play the music in the middle of the night, now your MP3 player needs a clock. That clock may drift, or it may drop out completely when the power goes out, unless you synchronize that clock over the network. But if you have network on your MP3 player, you may as well let it subscribe to the multicast stream instead of reading the stream from internal storage. If you do no…

Yeah, this is if you just want your playlist on loop 24/7, which seems reasonable in many scenarios.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#105

Post by t0bia_s »

radicality wrote: post #48
t0bia_s wrote: post #36

Site is blocked by NextDNS.

Which rules? Works for me on Nextdns. I have the “NextDNS Ads & Trackers”, and “Adguard DNS” blocklists enabled, and I think also enables every non-beta feature under Security.

Energized Blu Go

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#107

Post by rhacker »

ajsnigrutin wrote: post #92
sublinear wrote: post #73

Earlier quoted context omitted.

> to the intended recipient who can decode the steganography Not just decode, but also decrypt. You'd probably want to encrypt not just for the secrecy, but so that the noise introduced by the steganography doesn't seem so suspicious.

This would work if the elevator music was a never-repeating stream. With most elevator music, it's a few minutes of a "song" playing on repeat 24/7, so if you recorded a few repetitions of the "song", you'd probably see also repeated packets on the network. If the music was repeating but the stream was different all the time, then steganography could be the reason :)

I haven't actually heard elevator music as much as people say it exists.

In fact I don't think I've every been on an elevator that had music.

Re: Reverse engineering a mysterious UDP stream in my hotel (2016)

#110

Post by Salgat »

paisawalla wrote: post #52
Salgat wrote: post #40

Earlier quoted context omitted.

It'd be far more trivial to put a wireless speaker in an elevator than it would be to reverse engineer this.

Hotels are reasonably protected to such an attack. There are almost always cameras in the elevator, and the electronics are typically, to some extent, tamper-resistant.

It's not hard to subtly stick a small flat wireless speaker to the wall, and by the time they notice it the attack is already complete.
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