9 ms·
New 'negative light' technology hides data transfers in plain sight
- charcircuit 7mo agoIt seems simpler to use a secure radio protocol instead of relying on security by obscurity for communication.
- StevenWaterman 7mo agoA covert signal is still beneficial even if the signal is secure. The existence of the signal is valuable metadata. For a contrived example, imagine I'm in a warzone: - Secure = Enemies can't read my messages. Good. But they can still triangulate my position. - Covert = Enemies don't know I exist
- pinkmuffinere 7mo ago+1. As another example see https://en.wikipedia.org/wiki/Numbers_station https://en.wikipedia.org/wiki/Numbers_station -- people can't decipher the messages, but they strongly suspect something spy-y is going on. If they couldn't even detect it, there would be no suspicion. Also hi StevenWaterman, I recognize you from previous comments! I think this is the first time that's happened to me on HN
- applfanboysbgon 7mo agoAnother example: in some regimes merely using Tor is illegal, or say in the US using it is enough to justify a search warrant for probable cause, with no evidence of any actual wrongdoing. The EU Chat Control lobby is also trying very hard to criminalize encryption. The simple act of trying to communicate privately is taken as indicative of criminal wrongdoing in the modern world. Being able to communicate without adversarial parties knowing you're communicating is a boon.
- ranger_danger 7mo ago> in the US using it is enough to justify a search warrant for probable cause, with no evidence of any actual wrongdoing Source:
- mvrckhckr 7mo agoUnless they have "the right equipment". Then you are right back at the same situation.
- TeMPOraL 7mo agoNobody has "the right equipment" everywhere all at once, especially not with operators (human or otherwise) set to monitor it all the time. In the real world, obscurity is the cornerstone of security.
- mvrckhckr 7mo agoIf you know it exists and becomes popular, in the right situation you will make sure to have it. The dynamics don't change with this.
- TeMPOraL 7mo agoAlso even if they know you are transmitting, it may still be beneficial to prevent them from knowing how much you are transmitting. Imagine the enemy detects some of your transmission, even knowing it's encrypted, they can still look at the data rate (or estimate order of it): - 5 bps = probably a random transmitter, maybe audio spy device, maybe remote detonated weapon - 5 Mbps = probably a feed from military hardware or personnel Similar inferences can be made about volume, if they can identify distinct transmissions. Etc. If tricks like these can make the enemy confuse 5 Mbps TX for a 5 bps one, it has obvious tactical utility.
- jkhdigital 7mo agoSecure channels can still be jammed. Undetectability is a fundamentally different goal than secrecy.
- bob1029 7mo agoDSSS is sort of both security and obscurity at the same time. The very act of spreading your spectrum out via a secret key also has the effect of reducing the amplitude of your transmission, ideally below the noise floor. A receiver on the other side wouldn't see anything except noise unless they had the same key.
- adrian_b 7mo agoThe same is true for any other method of spread spectrum modulation, e.g. for FHSS (frequency-hopping spread spectrum) or for ultra-wideband pulses. The detection of weak signals requires long integration times, which remove from the output any spread spectrum signal present in the input, unless you know and apply before the integration the correct scrambling or frequency-hopping sequence.
- hmmokidk 7mo agoI am sure you could encrypt the warmth message somehow.
- esseph 7mo agoUnless your adversary is scanning for RF emissions, which is getting more and more common.
- adrian_b 7mo agoA lot of spy movies or police procedural movies show someone coming with a magic detector for hidden spying cameras or microphones that is used to sweep a room and remove all offending devices. The device presented in the parent article would be undetectable by any classic detectors. However, if such a method would ever become widely used in reality, it would not be difficult to make detectors for it. So it could have a window of opportunity, between the first development of spying devices based on it and the development of countermeasures.
- thatcherc 7mo agoLink to the paper: https://www.nature.com/articles/s41377-025-02119-y https://www.nature.com/articles/s41377-025-02119-y From the abstract: > Here, we demonstrate a covert communications method in which photon emission is rapidly electrically modulated both above and below the level of a passive blackbody at the emitter temperature. The time-averaged emission can be designed to be identical to the thermal background, realizing communications with zero optical signature for detectors with bandwidth lower than the modulation frequency It sounds like maybe they're modulating the emissivity of a diode up and down so that over time, its IR spectrum looks like black body radiation. Only someone looking at the intensity of the thermal radiation coming from the diode at really fast timescales (kilohertz or megahertz) would notice that there was a signal being transmitted.
- mojomark 7mo agoYep. I guess it was "hidden" until they published the method to detect the signal.
- TheOtherHobbes 7mo agoMaybe I'm missing something, but this reads like a complicated way to say "We made an IR diode that gets cold as well as hot."
- thewanderer1983 7mo agoYep.
- RobotToaster 7mo agoYeah, but saying that doesn't get the military to give you money.
- JellyBeanThief 7mo agoI would much rather have been called a computerologist than a computer scientist.
- TeMPOraL 7mo agoOr you can call it encryption along different axis. Much like extracting GPS signals from below thermal floor level - you can do it if you 1) know it's there, and 2) know exactly how to key in. It's impressive as heck, but you can always rephrase it in terms of information theory in ways that makes it sound like slightly different shade of mundane.
- scottyah 7mo agoIt's impressive how this article made this sound like a breakthrough, didn't even mention the entire historied field of steganography once.
- jkhdigital 7mo agoThe paper itself mentions steganography in the second sentence at least.
- dustfinger 7mo ago> Only a receiver with the right equipment can pick up the hidden message. So all an eavesdropper has to do is setup the right equipment then? I guess it is only invisible until the technology becomes more widely available.
- behehebd 7mo agoAs invisible as radio signals then.
- Hobadee 7mo agoNow now... Let's be fair... Radio broadcasts to everyone. Light you can block off to a single direction. Oh wait, directional radio antennas exist. Nevermind, yes. Exactly like radio waves.
- TeMPOraL 7mo ago> Light you can block off in a single direction. Sorta, kinda. You're really only just attenuating things a lot. It's tricky to actually block it off fully. Same with radio waves, as light is literally the same phenomena as radio waves, it's just shaking faster.
- behehebd 7mo agoAlmost like its all electromagnetic waves
- adrian_b 7mo agoIn general, it is very easy to detect that radio signals are present. A better comparison is with radio signals for which a method of spread-spectrum modulation has been used, chosen such as to have a bandwidth so wide that the averaged signal falls below the thermal noise level. Such radio signals will also not be detectable without special detectors. WiFi and Bluetooth use spread-spectrum modulation methods but they have relatively low bandwidths, so they can be easily distinguished from thermal noise. Much wider bandwidths are required to prevent detection.
- 7mo ago
- Retr0id 7mo ago> We do have encryption methods, but at the same time we’re always having to create new encryption methodologies when bad actors find new decryption strategies. > But if someone doesn’t even know the data is being transferred, then it’s really very hard for them to hack into it. If you can send information secretly then it definitely helps to prevent it being acquired by people you don’t want to access it. Very strange framing. Symmetric cryptography has been "unhackable" for a while now, for all intents and purposes. The real advantage is surely that nobody notices you're transmitting data at all?
- nine_k 7mo agoThe cypher may be prefectly impenetrable, but the software running on the transmitter or receiver may be more brittle. You cannot attack what you don't even know exists nearby.
- nyc_data_geek1 7mo agoMakes me look at steganography in slips on sunglasses an entirely new light.
- deleted 7mo ago[deleted]
- LoganDark 7mo agoI don't understand what makes it hidden if anyone with the right equipment can pick it up. That's like calling X-rays hidden because most cameras can't pick them up.
- mnw21cam 7mo agoTrue. I think the novel point is that on average, the emitter just isn't emitting. Normally, you can have a very simple piece of equipment that can pick up the fact that a signal source is emitting something, but then you need to get a more specialised piece of equipment to actually collect and decode the transmission. This just raises the stakes to having to have the specialised equipment to see that there is a transmission at all.
- userbinator 7mo agoThis is basically spread-spectrum / CDMA, but in a different frequency range? As others have mentioned in comments here, GPS signals are already far below the thermal noise floor.
- mapt 7mo agoSo it's a camouflaged semaphore?
- schobi 7mo agoMaybe I skipped over it, but the (suspected) narrow band emission of their diodes is something that could be detectable. Electronic warfare is not about listening, but just seeing the location of the emitter. If you had someone with a different thermal camera/ camera with SWIR, you might see that something is just not right.
- briandw 7mo agoThe “emitter” can either produce more thermal photons than the background thermal noise or fewer. Because it absorbs thermal energy particles of the time and loses that energy at others, it balances out to background. You have to know at what temporal frequency to sample to see it, otherwise the signal will integrate to zero. Very clever.
- ALLTaken 7mo agoBetween 2013 and 2015 I was working on UWB (Ultra-Wideband-Radar). It's stealth, undistinguishable from background noise too. Of course that depends on multiple attributes, but in general the signal can be understood like a chirp within multiple frequencies, thus looking non-linear and especially hard to detect, if there are multiple such devices additionally communicating with each other. Orbital Angular Momentum (OAM) makes it even more efficient at being stealth, without diving too deep into it. So this negative-light technology is quite interesting in that it's stealth, but it has to come a long way to reach the ubiquity of UWB. I'm curious if and how such technology could be used in space though. Happy to hear more! One of the most plaguing questions I have is that it's very odd that specialists are so quite about the wide-spread integration of UWB chips in all modern phones and the accompanying "possible" surveillance nightmare. As a government it'd be total horror to be fully penetrated by an adversary like this. If you find otherwise please share the paper here, there's a lot of literature about UWB, OAM, beam-forming, antenna-design and related technology that, when put together easily make someone doubting it at least more inclined to be more open. My work back then was sold to military by one of my professors behind my back, and after confronting the professor about it he laughed it off telling me it's normal and okay. I refused to publish about it, as I was finding it difficult to find a positive usage scenario, plus he was profiting of off my work that I needed for a grade financially outside of university and of course of no intention of integrating my work. To add salt to that wound he instructed me to change my applied-science paper to be more of a guide for a few select PhDs who'd receive the financial grants, making my work a footnote at best. I have no words. Later I learnt by a friend working on his Dr. degree how he got betrayed by his Dr Father. He was working on a science-backed improvement for a factory, after telling his Dr. Father he found that he patented the technology and sold it to the factory. When he found out, he heard a similar story to mine, where his Dr. Father basically told him, "lesson-learnt, better me than someone else". He finished his degree and kept his profile-low for years after that to not cause conflict.. quite sad. My initial plan was to provide IPS to the campus with a few-cm accuracy and gesture recognition through walls as a cool gimmick with future work focusing on accessibility scenarios. But with current devices it's possible to use the UWB chips in distributed mesh (similar to find-my) to create an ultra-high-resolution 3D-feed with city-wide, real-time and through-wall sensing at mm-accuracy. I'm not even factoring in resolution upgrades using AI. Cook me, if you want, this was genuine scientific work taking months of work back in 2015 to be able to build, but being backstabbed by your professor was quite unreal to find out. Later I got similar signals from friends at Fraunhofer and Max-Planck. Just listening to their work stories made clear they were fooled doing science, when they in tandem were quite frankly building military reconnaissance technology, but distributed in small disconnect groups of low-paid scientists (PhD/Dr/MSc).