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Defeating a 40-year-old copy protection dongle

dmitrybrant.com

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Re: Defeating a 40-year-old copy protection dongle

#151

Post by rustyhancock »

dehrmann wrote: post #3

> I must say, this copy protection mechanism seems a bit… simplistic? A hardware dongle that just passes back a constant number? 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.

The tool of choice back then was SoftICE and it would have been trivial to trap even bios level LPT access.

More to the point the guy didn't even open the dongle, which in all likelihood was a simple set of logic gates in this case.

I'm assuming he did have a careful look at the caller to the function because his reasoning that the communicating function took no inputs is faulty.

What if the hardware has a LFSR in it and returns changing responses, and the caller can check them with a verify function else where that maintains a state and knows to expect the next in the sequence?

We have far better tools today for sure, but we understood the system better back then. The right tool is sometimes better than a sharper tool as they say.

Edit : I should add I'm aware it's very likely the actual reversing involved more steps and checks than Dimitrys blog which is narrowed to what worked.

Re: Defeating a 40-year-old copy protection dongle

#152

Post by direwolf20 »

charcircuit wrote: post #141
direwolf20 wrote: post #139

Earlier quoted context omitted.

So when I buy a CD, I can install the software, and then grind the CD into powder, and since what I bought no longer exists, I can stop paying?

Well the software could disable itself when you stop paying. You stop paying for the value, the software stops providing you value.

Could the molecules from the food stop forming parts of my body?

Re: Defeating a 40-year-old copy protection dongle

#153

Post by direwolf20 »

lazide wrote: post #93
ryandrake wrote: post #53

Earlier quoted context omitted.

Seriously, I have a house full of appliances, tools, clothing, and so on, that I get "ongoing value" from and whose manufacturers don't have the gall to try to charge me monthly for. Totally unacceptable business model.

As long as no one expects updates and ongoing support beyond some pre-agreed time. The issue is a mismatch of incentives - customers wanting things for free - even if they aren’t actually customers. Vs businesses need/want for ongoing revenue (ideally for free too!). Both sides are never going to be perfectly happy, but there are reasonable compromises. There are also extractive abusive psychos, of course.

There was a comment here recently — someone complained that SoundCloud doesn't treat "former paying customers" well. This complainant was a "former paying customer".

Free customers can store 3 hours of sound. This former paying customer had more than 3 hours of sound stored.

The comment said SoundCloud was a terrible company holding their data hostage, by not letting them do anything with it except delete things to get it under 3 hours, and threatening to delete all of it if they didn't.

https://news.ycombinator.com/item?id=46783575

Re: Defeating a 40-year-old copy protection dongle

#154

Post by xp84 »

dataflow wrote: post #35
nsoonhui wrote: post #27

I write civil engineering software [0] and am familiar with this kind of dongle. Yes, even today there are users who want this kind of dongle instead of, say, cloud-based validation. They feel secure only if they have something tangible in hand. 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. Als…

> 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. Why should users upgrade or keep paying you when they already bought what they need and don't need anything else?

Honestly, if they never need anything more from the developer, a perpetual license and never spending another dime seems fine. However, in modern times, OS vendors (especially one named after fruit) tend to break a ton of APIs and change rules with every "major release," meaning developers have to invest a ton of effort to at minimum meet all those new requirements every year (!) or else the app will at best look out of place, more likely look totally screwed up and exhibit sudden "bugs" due to the unexpected OS changes, or at worst, crash.

Then users are suddenly all over the developer to provide an update "so I can use this on Tahoe" or whatever, and unless the application is in its honeymoon period where new sales suffice to keep money flowing, the developer is gonna need recurring revenue in order to do recurring development.

Re: Defeating a 40-year-old copy protection dongle

#156

Post by direwolf20 »

TheDong wrote: post #115
odomus wrote: post #55

Is defeating a 40-year-old copy protection mechanism still illegal under Section 1201 of the DMCA, or have they changed the law to make an exception for "very old" software?

Once it hits 70 years from the lifetime of the author (so probably another 80 or 90 years from now) and is in public domain, that might change things since there will no longer be copyright being protected. In terms of copyright terms, this software is still pretty young, not even halfway to public domain. It's disrespectful to call it "very old".

Defeating a copy protection measure is illegal, even if the copy protection measure is not copyrighted.

Re: Defeating a 40-year-old copy protection dongle

#157

Post by direwolf20 »

mrandish wrote: post #109
Sophira wrote: post #75

The fact that the software and hardware is evidently still in use at some companies gives me pause about whether releasing it in a cracked form publicly after having published it on a personal website would be a good idea. Software companies love to milk enterprises for all their worth, because they're the entities who will pay the most amount of money if it means that the software they use can still work - and a big…

Another poster found grabs of the company's website on archive.org. The last date it existed to be grabbed was in 2001. I think the OP is fine on this one. Other than that, there's virtually no mention of the company or software anywhere online. Just to put that in context, I'm in the vintage computer / software community where thousands of amateur historians and archivists scour obscure corners looking for old, unkn…

They could have been bought by a bigger company. You never know until you get sued. If the copyright isn't registered, and often even if it is, there's no way to know who owns it now.

If you're legally daring, and you get sued, you can try to force them to prove they own the copyright. There's often not enough documentation of this sort of thing. People have gotten away with not paying their car loans because after several loan sales and company mergers, the company that owns it can't prove they do, so effectively nobody owns it and it doesn't exist.

Re: Defeating a 40-year-old copy protection dongle

#160

Post by xp84 »

SecretDreams wrote: post #32
nsoonhui wrote: post #27

I write civil engineering software [0] and am familiar with this kind of dongle. Yes, even today there are users who want this kind of dongle instead of, say, cloud-based validation. They feel secure only if they have something tangible in hand. 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. Als…

> 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 This take is diametrically opposite to what end users need. In a world where "if it ain't broke, don't fix it" is perfectly fine for the end user, buying a one off license for a software seems much more sane then SaaS. SaaS is like a plague for end users.…

> "if it ain't broke, don't fix it" is perfectly fine for the end user

That's okay, but in say, 2 years when Mac OS 28 completely bricks the app, the developer will not be there to give you an updated one (even if you're willing to pay), since most of the addressible market already bought the app in 2025, and after 2 years with almost no revenue, the developer stopped working on it, deleted the repo and moved onto another project. The developer can't even rely on a future OS update "encouraging" people to buy "App (N+1)" since it might be "ain't broke" for 1 year, or for 5.

The point of a subscription is not to rip you off, it's to acknowledge a few realities:

1. For reasons beyond developers' control, platform vendors do not provide a "permanent" platform, but a shifting one without any long-term guarantees. You can put a 100-year certificate into your app, but the OS vendor might decide that only certs with expiration less than 45 days are okay and your app no longer works unless you're around to (A) keep abreast of the platform's rules and changes, and (B) ship an update.

2. Many software offerings need to provide a server-side component, which is never a one-time cost.

3. Relying on upgrade purchases to sustain a product gives developers perverse incentives to shove a ton of new features just to be able to pitch "Upgrade to Appitron 2!" with a ton of bullet points, whereas subscription pricing incentivizes them simply to keep users loving the app forever, including adopting new technologies but also just improving the core experience.

Due to 1 and 2, it makes sense to let users who stop using the program after a short time pay very little, and to let users who rely on the continued operation of the program, pay a little bit each year, instead of paying $500 once and using it for a few years, and maybe upgrading for $250.

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