I made a CTF challenge for this year's BSidesSF CTF where players were given a CDDA audio file (just raw PCM samples) which when burned on a CD-RW would produce an image of the flag. (The idea was not for them to burn the audio, since they'd need to guess my exact CD-RW or else they wouldn't get an image readable enough to be useful. Instead they were supposed to invert the process in software and simulate what a burned disk would look like, in a way that let them adjust disk parameters rapidly until they had a readable image.)
The challenge took me a few weeks to make because "calibrating" a disk (determining the geometry of the pregroove) is incredibly sensitive.
After the CTF I tried really hard to make a repeatable calibration process with the intent of building something releasable. I even ended up measuring the details on every CD-RW and CD-R I could buy on Amazon.
But despite trying very hard, I never did make calibration patterns that were reliable enough that I felt like other people would be willing to go through the process.
It seems someone else has succeeded where I failed. Great to see!
A capture the flag challenge (CTF) is a common cybersecurity challenge in which you are tasked to hack/reverse engineer/pwn a system or something else which falls into the category of abusing a system for different gains. There are different sites online for you to get into hacking and CTFs are just one category.
> In 2012, a LightScribe optical drive was successfully used by Maher El-Kady, a graduate of UCLA, to turn a specially prepared graphite oxide layer coated onto a DVD into graphene.[10] El-Kady and Richard Kaner, his lab professor, used an unmodified LightScribe drive. The disc was prepared by coating the disc with an aqueous solution of graphite oxide and allowing it to dry. Areas of the coating illuminated by the LightScribe laser were turned into graphene. Various shapes can be drawn, which allowed the scientist duo essentially to laser-print an ultracapacitor on graphene using consumer-grade technology.
Now you are telling me we could potentially have “the DVD is the computer”. Imagine printing not just a capacitor but a whole PCB and soldered components, putting the innards of like a Raspberry Pi on top of a specially crafted DVD that has said single-board on one side and a readable DVD surface on the opposite side! :D
there was an inkjet printer that had a special tray for CD/DVDs
the intent was to add artwork to the discs, but if you put a copper-plated board in there, printed on a circuit board, and etched away the area left behind, you'd be almost there :)
drilling holes and thru plating is my least favorite step tho
I have a LightScribe compatible external CD/DVD burner. It came with a LightScribe disc that I haven’t taken the plastic off still to this day. Since it only came with a single one I could never decide which one thing to use that one LightScribe disc for, back when I was still burning things on CD and DVD.
You didn't miss much. It took 20-30 minutes each pass, plus the extra cost for the discs.
But even if you were fine with that, it came out too light under actual lighting conditions, even after you burned it twice, which defeats the use case of making it look professionally labeled. For home use, a Sharpie beat it in every way.
Huh, that wasn't my experience. I mean, it absolutely was slow especially with sufficiently complex labels, but they generally came out fine. Granted, you absolutely couldn't just drop any arbitrary image into the LightScribe software and have it come out looking good, you'd have to mess with the contrast, but black-and-white text and line art would come out fine. And more legible than Sharpie, with my handwriting.
For a very low-sales side business (my father's hobby) the discs looked sufficiently professional to impress the people buying them — mostly his friends.
i'm like that in anything vaguely RPGish, videogame/board-top/cards/whatever.
if there is a such thing as a potion or anything like it i'll horde it and never use for fear of needing it in the future, well past the last boss or the credits..
I'm kinda opposite on reason, I feel like using one means I failed to do the battle the normal way and picked the easy mode.
I've mostly healed from that affliction, at least for buyable consumables, now it is just math, if I buy X potions I won't have to go back to rest and heal, so it's more efficient to grind while spending a bit of gold earned on regen
I've noticed this a few times where I've hoarded items to use later only to find I've finished the game before that challenging "later" arrives.
For some odd reason, the specific game that comes to mind for this was Horizon:Zero Dawn PS4/5.
Conversely, I'm playing Half-Life:Blueshift right now, and I didn't try to save anything, now I've hit a couple of points where I'm out of ammo or health and can't progress without loading an older save.
I had one fun experience in Black Mesa (HL fan-remake) where I was knocked off of the edge of a "cliff" by a large enemy (no spoilers) and it auto-saved mid-air, so it reloaded me falling forever >_<.
I'm definitely the type to always be saving items "just in case" and the Half Life series is definitely one where I felt the most paranoid about that.
I played HL1 on the PS2 recently with a memory card that was really limited in space so I was only managing a single save for most of the playthrough until I soft locked myself in a room I couldn't leave using my ONLY save and had to start at least carrying a second backup save to prevent that happening again.
Half Life 2 felt like it almost made fun of me at times for building that hoarding mentality, always dumping health and ammo on me when I had already been preserving it as much as possible right before. Meanwhile the few things I would run out of it would never give any more of for entire sections.
> I played HL1 on the PS2 recently with a memory card that was really limited in space so I was only managing a single save for most of the playthrough until I soft locked myself in a room I couldn't leave using my ONLY save and had to start at least carrying a second backup save to prevent that happening again.
I get very little time to game these days, which has the benefit that I have saves usually spaced no more than about an hour apart. Sometimes a couple of hours on the weekends. There were a couple of points in HL1 where I had to go back to a previous save because I was in a bad situation, I'm playing on PC so there was no real limit on the number of saves I can keep.
I've not started HL2 yet (this time around, and it's been 20 something years since I last played it) so I can't remember what that was like.
I'm going to finish Blueshift, then go on to HL2, but I'd really like some texture and quality updates; HL2 is a real downgrade from Black Mesa. I tried it in VR but was feeling nauseous within a few minutes.
All of this is to lead up to Alyx on my Steam Frame which is just sitting there waiting until I replay these so I can remember what happened.
> Half Life 2 felt like it almost made fun of me at times for building that hoarding mentality, always dumping health and ammo on me when I had already been preserving it as much as possible right before. Meanwhile the few things I would run out of it would never give any more of for entire sections
I'll bear this in mind. I think HL1 was a little too obvious; you suddenly get a cache of rocket ammo, you know what's coming.
Me but with notebooks. Not unique or interesting ones. All of them. I'm always worried about ruining the notebook by putting the wrong stuff in it so I just have an ever increasing collection of blank notebooks that I thought were definitely the one I would finally use.
I haven't worked with paper in a long time, but IIRC some notebooks I used in school had pages you could tear out, sacrificing a strip along the side, while preserving holes that'd work in a 3 ring binder. So then you could just write anything in one of these notebooks, tear it out, and put it in a 3 ring binder afterward. The binder could be more thematically organized then, separate binders by subject. A bit like opening your text editor, writing stuff down, then deciding which dir to save it to later.
Also even if your paper doesn't have the holes, you could use a punch to add them, assuming you have space on the side without writing.
I used to have a label system called Neato, which provided round CD labels you could make on a printer, along with a tool to press them accurately onto the non-recording side of a CD-R. There were even transparent labels, so the resulting disk looked like a commercially produced disk.
Lots of new USB DVD drives are available from brands I've never heard of. But the availability of Bluray drives is so low I suspect they're only new old stock.
You should look for Blu-ray drives instead of Bluray which does not exist /s
Back around 2007 during the red vs blue HD laser format war, the spelling was hammered into me as the incorrect spelling was tirelessly brought to one's attention. Since we're going down memory lane on shiny discs, I couldn't resist bringing this one back too
Probably. Bluray still exists, still a popular medium for selling games on PS/Xbox and to certain extent movies to people who like to watch on their high-end equipment.
Absolutely. And discs as well. I had an x-ray recently and asked them to give me the image so I could take it to a different clinic, and they burned it onto a CD. So I suppose optical media is sort of irreplaceable for medical applications at least.
The thing is that sometimes you just need a cheap physical medium you can give away. Sure cloud is an alternative, but it's a bad one, since it costs money to keep online. A CD or a floppy is something you record and forget. And USB sticks are much more expensive and can be a security risk.
I can't comment on this particular project, but I know that similar projects have allowed adding images to the unused portions of the disc. A given region of the disc cannot be both image and data, but the disc can contain an inner region of data and imagery in the outer unused portion.
DVD codec probably allows for a certain amount of error correction to recover from scratches, images can still look readable to humans despite a bit of noise, I wonder if there’s enough overlap there to meet in the middle and have an image that also stores data
A bit like those AI images that were also working QR codes from a while back.[1]
Would be a really interesting challenge to find the point where maximally useful data meets a maximally good image. The data goes through layers of encoding to become data on disc, so it wouldn't be easy, but we already have a one-way translation here in this tool.
What do you mean by that?
I don't think the laser writes data into the label usually. There is a reflective layer though, that will be damaged easily when scratching or peeling off the label.
The challenge took me a few weeks to make because "calibrating" a disk (determining the geometry of the pregroove) is incredibly sensitive.
After the CTF I tried really hard to make a repeatable calibration process with the intent of building something releasable. I even ended up measuring the details on every CD-RW and CD-R I could buy on Amazon.
But despite trying very hard, I never did make calibration patterns that were reliable enough that I felt like other people would be willing to go through the process.
It seems someone else has succeeded where I failed. Great to see!
> In 2012, a LightScribe optical drive was successfully used by Maher El-Kady, a graduate of UCLA, to turn a specially prepared graphite oxide layer coated onto a DVD into graphene.[10] El-Kady and Richard Kaner, his lab professor, used an unmodified LightScribe drive. The disc was prepared by coating the disc with an aqueous solution of graphite oxide and allowing it to dry. Areas of the coating illuminated by the LightScribe laser were turned into graphene. Various shapes can be drawn, which allowed the scientist duo essentially to laser-print an ultracapacitor on graphene using consumer-grade technology.
Now you are telling me we could potentially have “the DVD is the computer”. Imagine printing not just a capacitor but a whole PCB and soldered components, putting the innards of like a Raspberry Pi on top of a specially crafted DVD that has said single-board on one side and a readable DVD surface on the opposite side! :D
the intent was to add artwork to the discs, but if you put a copper-plated board in there, printed on a circuit board, and etched away the area left behind, you'd be almost there :)
drilling holes and thru plating is my least favorite step tho
But even if you were fine with that, it came out too light under actual lighting conditions, even after you burned it twice, which defeats the use case of making it look professionally labeled. For home use, a Sharpie beat it in every way.
The disc shown on https://en.wikipedia.org/wiki/LightScribe looks normal.
if there is a such thing as a potion or anything like it i'll horde it and never use for fear of needing it in the future, well past the last boss or the credits..
I've mostly healed from that affliction, at least for buyable consumables, now it is just math, if I buy X potions I won't have to go back to rest and heal, so it's more efficient to grind while spending a bit of gold earned on regen
For some odd reason, the specific game that comes to mind for this was Horizon:Zero Dawn PS4/5.
Conversely, I'm playing Half-Life:Blueshift right now, and I didn't try to save anything, now I've hit a couple of points where I'm out of ammo or health and can't progress without loading an older save.
I had one fun experience in Black Mesa (HL fan-remake) where I was knocked off of the edge of a "cliff" by a large enemy (no spoilers) and it auto-saved mid-air, so it reloaded me falling forever >_<.
I played HL1 on the PS2 recently with a memory card that was really limited in space so I was only managing a single save for most of the playthrough until I soft locked myself in a room I couldn't leave using my ONLY save and had to start at least carrying a second backup save to prevent that happening again.
Half Life 2 felt like it almost made fun of me at times for building that hoarding mentality, always dumping health and ammo on me when I had already been preserving it as much as possible right before. Meanwhile the few things I would run out of it would never give any more of for entire sections.
I get very little time to game these days, which has the benefit that I have saves usually spaced no more than about an hour apart. Sometimes a couple of hours on the weekends. There were a couple of points in HL1 where I had to go back to a previous save because I was in a bad situation, I'm playing on PC so there was no real limit on the number of saves I can keep.
I've not started HL2 yet (this time around, and it's been 20 something years since I last played it) so I can't remember what that was like.
I'm going to finish Blueshift, then go on to HL2, but I'd really like some texture and quality updates; HL2 is a real downgrade from Black Mesa. I tried it in VR but was feeling nauseous within a few minutes.
All of this is to lead up to Alyx on my Steam Frame which is just sitting there waiting until I replay these so I can remember what happened.
> Half Life 2 felt like it almost made fun of me at times for building that hoarding mentality, always dumping health and ammo on me when I had already been preserving it as much as possible right before. Meanwhile the few things I would run out of it would never give any more of for entire sections
I'll bear this in mind. I think HL1 was a little too obvious; you suddenly get a cache of rocket ammo, you know what's coming.
Also even if your paper doesn't have the holes, you could use a punch to add them, assuming you have space on the side without writing.
This was followed up by Labelflash in 2007(2).
(1) https://en.wikipedia.org/wiki/DiscT@2
(2) https://en.wikipedia.org/wiki/Labelflash
Back around 2007 during the red vs blue HD laser format war, the spelling was hammered into me as the incorrect spelling was tirelessly brought to one's attention. Since we're going down memory lane on shiny discs, I couldn't resist bringing this one back too
XBox is making similar moves but isn't committing 100% to the bit yet.
One would think that some sort of common EDI would have come around by now.
https://en.wikipedia.org/wiki/DiscT@2
And I suppose the other repo that does this already
https://github.com/arduinocelentano/cdimage
Would be a really interesting challenge to find the point where maximally useful data meets a maximally good image. The data goes through layers of encoding to become data on disc, so it wouldn't be easy, but we already have a one-way translation here in this tool.
[1] e.g. https://www.reddit.com/r/StableDiffusion/comments/141hg9x/co...
A fellow xth grader did a science project on this, and I’ll never forget it.
The plastic is purely for protection and rigidity, the "label" is the actual functional part of the disc.
I wonder if the disk can still hold data at the same time.