Defeating a 40-year-old copy protection dongle
by zdw on 2/1/2026, 9:30:51 PM
https://dmitrybrant.com/2026/02/01/defeating-a-40-year-old-copy-protection-dongle
Comments
by: ruleryak
Many a crack back in the day was even more simple still, we'd just find and alter the right JE or JNE into a JMP and we're off to the races. As the author found, the tough part is just finding and interpreting where and how the protection was implemented. If throwing the exe in a hex editor gave you access to String Data References (not always the case, but more common than not) then you'd just fail the check you were trying to skip, find that string, hop over into assembly to see what triggered loading that, and then just alter the logic to jump over it when the time comes.
2/1/2026, 11:05:23 PM
by: nsoonhui
I write civil engineering software and am familiar with this kind of dongle. Yes, even today there are users who <i>want</i> this kind of dongle instead of, say, cloud-based validation. They feel secure only if they have something tangible in hand.<p>Since we sold (and still sell) perpetual licenses, it becomes a problem when a dongle breaks and replacement parts are no longer available. Not all users want to upgrade. Also, you may hate cloud licensing, but it is precisely cloud licensing that makes subscriptions possible and, therefore, recurring revenue—which, from a business point of view, is especially important in a field where regulations do not change very fast, because users have little incentive to upgrade.<p>Also, despite investing a lot of effort into programming the dongle, we can still usually find cracked versions floating online, even on legitimate platforms like Shopee or Lazada. You might think cracking dongles is fun and copy protection is evil, but without protection, our livelihood is affected. It’s not as if we have the legal resources to pursue pirates.
2/1/2026, 11:57:47 PM
by: dehrmann
> I must say, this copy protection mechanism seems a bit… simplistic? A hardware dongle that just passes back a constant number?<p>Seems like it was an appropriate amount of engineering. Looks like this took between an afternoon and a week with the help of an emulator and decompiler. Imagine trying to do this back then without those tools.
2/1/2026, 10:56:05 PM
by: aizk
Very cool to read an article about windows 95 still being used in production - a nice contrast to the infinite AI hype cycle over everything. Tech may move fast in flashy areas but not in the more "boring" parts of the industry.
2/1/2026, 11:16:48 PM
by: jedberg
> I must say, this copy protection mechanism seems a bit… simplistic? A hardware dongle that just passes back a constant number? Defeatable with a four-byte patch?<p>Nowadays we don't bother with copyright protection other than a license key, because we know enterprises generally will pay their bills if you put up any indication at all that a bill is required to be paid.<p>This was basically the 80s version of that.
2/1/2026, 11:58:40 PM
by: insuranceguru
wow, the home accountant is basically the great-grandfather of everything we do in modern financial and actuarial modeling. dmitry's breakdown is like digital archeology.<p>it’s wild to think about the hardware risk people used to accept putting your entire household's financial history on a system that bricks itself the second a 40-year-old plastic dongle fails. really great read.
2/2/2026, 12:14:17 AM
by: sonixier
The company i work at has the same problem. We have some old mission-critical windows 2000 pc that runs the rpg compiler, with attached dongle. This gave me some clues on where to start - thanks author!
2/1/2026, 11:27:54 PM
by: izme
This takes me back. There exist emulators for these dongles as well, you run the a dumper with the dongle attached and load the program and it makes a dump file which you then use in the emulator.<p>I had to do this for a company so they could continue to use their old specialised Win98 software on modern computers using Dosbox and an emulator.
2/1/2026, 11:54:07 PM
by: dunham
Back when I was a kid in the 80's. I cracked one of the Ultima games. I had it on my hard drive and didn't want to stick a floppy in every time I ran it.<p>The code decrypted itself, which confused debuggers, and then loaded a special sector from disk. It was a small sector buried in the payload of a larger sector, so the track was too big to copy with standard tools. The data in the sector was just the start address of the program. My fix was to change executable header to point to the correct start address.
2/1/2026, 11:34:36 PM
by: burnt-resistor
And they probably could've just used Neverlock Business which cracks zillions of programs.
2/2/2026, 12:19:22 AM
by: accrual
Fun journey! It would be fascinating to see what's inside the dongle. I wonder if it's programmable or just a simple circuit.
2/1/2026, 11:34:42 PM
by: kwanbix
My father, an accountant, used to have a program like that, that used RPG and a dongle! Good times. Horrible donle.
2/1/2026, 10:49:44 PM
by: dmitrygr
<p><pre><code> >Very importantly, there doesn’t seem to be any “input” into this routine. It doesn’t pop anything from the stack, nor does it care about any register values passed into it. Which can only mean that the result of this routine is completely constant! </code></pre> This is not necessarily a fair assumption (though it worked this time). It could be some sort of a rolling code, where the reply is not constant but changes, and remains verifiable. Example: garge door openers have no input from the garage, but the sent signal differs every button click, and the garage can verify its correctness
2/1/2026, 11:21:22 PM
by: catlikesshrimp
Why wasn't (isn't) this more widely used? It was clearly more effective than a cdkey.<p>I know there is cost associated with the hardware, but surely the costumer can cough 15 more dollars.<p>The only reason I can think of is wanting as wide adoption before max revenue as possible. But then, this has never been too popular, not even for games!
2/1/2026, 11:09:24 PM
by: huflungdung
[dead]
2/1/2026, 11:59:53 PM