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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

#11

Post by dwattttt »

15155 wrote: post #6
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.

Audience matters. Something intended to stop legitimate business consumers in a non tech industry requires substantially less sophistication than something built to withstand professional reverse engineers.

Locks are there to keep honest people honest.

To expand on the saying, they're not there to be insurmountable. Just to be hard enough to make it easier to do things the right way.

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

#12

Post by ok123456 »

catlikesshrimp wrote: post #9

Why wasn't (isn't) this more widely used? It was clearly more effective than a cdkey. I know there is cost associated with the hardware, but surely the costumer can cough 15 more dollars. 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!

It was widely used in engineering software because the license cost was equivalent to a large fraction of an engineer's salary. Anyone who used AutoCAD back in the 90s can remember.

When parallel ports were discontinued, they migrated to USB and network license servers.

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

#13

Post by classichasclass »

15155 wrote: post #6
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.

Audience matters. Something intended to stop legitimate business consumers in a non tech industry requires substantially less sophistication than something built to withstand professional reverse engineers.

Copy protection was also generally less robust for educational software, since it sold to generally law-abiding folks (parents, educators, etc.). Never saw Rapidlok or V-MAX! used for educational software on the Commodore 64, for example.

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

#15

Post by dmitrygr » 

  >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!
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

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

#17

Post by 1970-01-01 »

aizk wrote: post #14

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.

The screenshots show the program was made for DOS. Very likely Windows was used just for network file sharing.

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

#18

Post by iamflimflam1 »

opinologo wrote: post #5
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.

Iremember doing exactly this kind of hack for a small telco in Bueno Aires. Extel. Around the year 2000. In most cases it was not much more difficult than what OP described.

I worked on some software that was used by telcos around that time - you were probably hacking our dongles :)

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

#19

Post by jandrese »

catlikesshrimp wrote: post #9

Why wasn't (isn't) this more widely used? It was clearly more effective than a cdkey. I know there is cost associated with the hardware, but surely the costumer can cough 15 more dollars. 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!

One problem is that they often couldn't be daisy chained, the connector on the back was only useful for an actual printer. So if everybody started doing it you would have to swap them constantly which is a headache. So they're mostly used for software where it's going to be the only thing running on the box.

I find it interesting that they didn't make it into the USB era where you could easily have something that does some actual processing on the device that makes it a serious challenge to reverse engineer.

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

#20

Post 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.

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.

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