Not to be a wet blanket, but every time this comes up I get annoyed by some factual inaccuracies in the articles about this. It is not digital! He drew an image on a computer, but converted it to an analogue spectrogram to store on the bird. That's neat as hell, but it's not digital. The image that he got back was slightly corrupted.

Now I would be fascinated to see a follow-up seeing if you can actually modulate a digital signal and have is survive a round trip through the bird bit-for-bit accurate. I suspect in reality it would be much lower data rate, but definitely not nothing!

I believe the thread was automatically locked due to community reports and then a mod manually unlocked it?

As others have said, it is not entirely clear what you mean by sharp. Based on the rounded corner and button example you gave previously, I think it might just be the graphic design. MacOS has had a lot of time invested into its design language including subtle things like a thin, almost glass-like specular border around windows and then a drop shadow. This very much becomes a matter of taste in many cases, but for some it helps identify boundaries more precisely. Perhaps have a look at https://github.com/vinceliuice/WhiteSur-gtk-theme, which replicates MacOS as closely as possible. You may be able to experiment with it side by side and see if you can figure out exactly what design element it is that you are looking for.

Exactly. Digital logic, when implemented in analogue, generally have to have forbidden zones where a signal in that range is considerer invalid. Regardless of implementation, digital is about the discretized logic of the system. That is explicitly the whole point of digital: Minor analogue distortion does not change the information content of the signal unless it is so bad as to flip a bit.

I possibly should put greater emphasis on the fact that I am talking about the host key, not the client key. This guide is for a client identity key. I am talking about host keys as you find in /etc/ssh/ssh_host_ed25519, etc.

Quick search of the source turned up this: https://github.com/pop-os/cosmic-comp/blob/master/data/keybindings.ron

The whole sequence is:

• Digitally synthesized spectrogram (lossless)
• Played through a DAC and speaker to produce an analogue signal (lossy)
• Heard by the bird (analogue, lossy)
• Reproduced by the bird (analogue, lossy)
• Captured by an ADC as a digital audio signal (lossy)
• Spectrum-analysed to observe a similar (but corrupted) reproduction of the shape in the original spectrogram

To be transferring digital information, we would instead need to modulate and demodulate the digital signal (exactly like an old modem) so that the analogue corruption does not affect the digital signal:

• Image file (lossless)
• Bit stream (lossless)
• Analogue modulation of bit stream played through DAC (lossy)
• Heard by the bird (lossy)
• Reproduced by the bird (lossy)
• Demodulated to recover exact bit stream despite distortion (lossless again)
• Decode bit stream to recover original image file, bit-for-bit perfect

I extremely doubt that this bird is capable of 2MB/s. For reference that would make it 280+ times fast than dialup, and barely slower than ADSL. This setup is basically just using the bird instead of a telephone line.

Note: This incident is from February 2025, not recent news. This is a repost of one of their top articles of the year. I hadn't seen it originally, but it should probably be marked in some way as not being current as of time of posting.

Phonetics is the study of speech sounds. The phonetic alphabet is called that because each letter/word in the alphabet was chosen to be one that started with the corresponding phoneme and that the set of words were between them phonetically unambiguous. Phonics is a way of teaching reading and writing that is based on the phonetics of words and how they relate to the written form.

Yes, that would be a digital modulation. That is decidedly not what is being done with the bird. The input data is the "PNG" of the bird, which is then not digitally modulated, but converted to an analogue signal and later redigitized. If the file has been converted to a series of pulses at different frequencies (the equivalent of your black and white squares) that would be a digital modulation. I am not arguing that this is not possible. My original comment explicitly says I would like to see a follow up with actual modulation. But just because it is possible to run dialup over an analogue phone line does not mean that calling your grandma on that same phone is a digital communication system. Some computers back in the day could modulate and record data on commercial audio cassettes. That does not mean that if I record something off the radio and play it back later that's a digital copy of the song.

Got the client working (mostly) without issues again, though trying to imitate my process for host keys as closely as possible I did encounter some weirdness that led me to this open bug: https://bugzilla.mindrot.org/show_bug.cgi?id=3355 So that may be the source of my issues... If they keys I was using suddenly were secretly requiring touch, it would explain a lot. I can't right now but I will do another experiment with host keys when I can. Still would love to see if anyone else is able to reproduce this behaviour or get it working.

FYI I got it working, please see the update above.

I suppose you have caught me out slightly lacking in precision or pedantry. A digital to analogue modulation scheme is able to exactly reconstruct the original digital signal within the design tolerances for noise and distortion. Yes, eventually a signal may degrade or be corrupted, but prior to that point the reproduction is literally and exactly perfect. That exactitude is just about the definition of a digital system. This bird system is incapable of reproducing the input image of the bird exactly. It is not a digital communication system, unless you consider the "PNG" of the bird to have not been the message being carried.

This reads like a parody to me. They almost seem to be trying to find a way to warp and misunderstand even the most basic concepts to contort themselves to miss the point. I honestly am baffled as to how such a seemingly-contrived misinterpretation of absolutely everything at every step of the way could happen by accident. But I suppose the internet is a billion monkeys at a billion typewriters so maybe it had to happen eventually.

I previously have had no issues using this as a client key, but honestly I wouldn't put it past myself to have picked the wrong key and not noticed. Maybe I will give it another try, but I don't think that's it.

I am familiar with these alternatives. My experiment was specific in wanting FIDO2 and I ended up figuring out the issue. It was the intersection of a couple of weird behaviours that made debugging very confusing, but it works exactly as I expected it would once those are resolved. I guess we can consider this a proof of concept that you can indeed use FIDO2 tokens as an external SSH host key (though as I said below whether this is practically useful is another matter entirely).

Yeah, the rough idea is to use any old FIDO2 key as a USB HSM. Not necessarily looking for a very practical solution (the easy fix would be to just encrypt the drive), but curious. What inspired this, though not necessarily the final application, is Nix secret distribution tools that use the host key as the secret recipient. This means that theoretically if you have the host identity tied to an external HSM or similar you could have the same image deploy as different machines based on what security key you have plugged in.

Yes, the near-identical sentences (only drawing a distinction between the processes where one exists) would indicate that. The "heard by the bird" and "reproduced by the bird" steps were also the same. But this is necessary context to make clear the digital data ("bit-stream") that is being modulated into the signal.

It is far from "exactly the same". The similarity is only in that both go through the same analogue channel. The entire point is that the modulated signal can be reconstructed exactly, while the spectrogram cannot.

The article title says they converted a PNG and the bird was able to "recall the file", and yet it produced an indisputably different file. That it looks vaguely the same to the cursory human observer does not make it the same file.

Heads up that you should still be able to sideload over ADB (the origin of the term on android, after all) without the wait, so setting up a new device before the 24 hours are up is still doable.

Precisely... And digital modulation's entire purpose is for a digital signal to survive those distortions bit-for-bit perfect. Even if we call the digitally-generated spectrogram digital information, the bird simply did not reproduce it exactly. Whatever time, frequency, and amplitude resolution you apply to the signal, if it's low enough that the bird reproduced the signal exactly within that discretized scheme, then it simply did not achieve 2 MB/s. I would bet that the Shannon capacity of this bird is simply nowhere near 2 MB/s.