Whoah! That's an awesome find! 😁 These dongles apparently were very common in the 80s/early 90s.
Ironically, they motivated pirates even more to "fix" software using it.
Software companies never learned, it seems.
I'm really curious, too how the mechanism works. Just a bunch of diodes/resistors? a flip-flop? an EPROM? a microcontroller?

Yes, it's interested for sure 😄

Here is more info about it: https://www.jstor.org/stable/23060647

Here is the thread Fargo started over at the vcfed forums- https://www.vcfed.org/forum/forum/technical-s … rotected-ms-dos

My understanding is that dongles were primarily used in high end applications, such as Art Works for RiscOS like this one:

Using AI, managed to reverse the dongle encryption and simulate it

kokoboi wrote on Today, 16:29:

Using AI, managed to reverse the dongle encryption and simulate it

Wow! This is fantastic news! I hope you can share your method and post the unprotected copy to the Internet Archive.

Back in the era, that was mentioned in "Programmer's Technical Reference for MSDOS and the IBM PC" - http://www.o3one.org/hwdocs/bios_doc/dosref22.html

According to PC Week Magazine, July 4, 1988, Arabic versions of MSDOS are shipping with a hardware copy-protection system from R […]
Show full quote

According to PC Week Magazine, July 4, 1988, Arabic versions of MSDOS are
shipping with a hardware copy-protection system from Rainbow Technologies.
This is similar to the short-lived system used by AutoCAD 2.52 and a very few
other MSDOS programs, where an adapter block is plugged into the parallel port
and software makes use of coded bytes within the block. This type of copy
protection has been common on Commodore products for several years, where it is
called a "dongle."
The AutoCAD dongle was defeated by a small program written within weeks of
version 2.52's debut. Version 2.62 was released 3 months later, without the
dongle. The DOS dongle will, however, prevent the system from booting at all
unless it is found.
This makes the Arabic version of MSDOS the first copy-protected operating
system, a dubious distinction at best. The modifications to the operating
system to support the dongle are not known at this time. Frankly, it would
seem that burning the operating system into ROMs would be cheaper and simpler.

According to PC Week Magazine, July 4, 1988, Arabic versions of MSDOS are shipping with a hardware copy-protection system from R […]
Show full quote

According to PC Week Magazine, July 4, 1988, Arabic versions of MSDOS are
shipping with a hardware copy-protection system from Rainbow Technologies.
This is similar to the short-lived system used by AutoCAD 2.52 and a very few
other MSDOS programs, where an adapter block is plugged into the parallel port
and software makes use of coded bytes within the block.

Hi, I'm afraid that includes a tiny bit of US defaultism.
The statement is true for North American releases, but not the European ones.
Over here in former Western Europe, the AutoCAD dongle was kept way into the mid-90s!
It was so annyoing, especially to laptop users or users or OS/2 etc. were the dongle couldn't be accessed.
That's one of the reasons my dad had bought a pre-2.52 AutoCAD, I vaguely remember.
That version could be easier used to demo computing power of PCs he sold.
Not sure about Eastern Europe, though. Copyright laws were more lax over there, I guess, so unprotected versions of newer releases might been into circulation.

Jo22 wrote on Today, 17:27:

Over here in former Western Europe, the AutoCAD dongle was kept way into the mid-90s!

Indeed - I recall installing AutoCAD R13, on a machine with Covox-like LPT DAC.
When trying to run the program, there was a noise heard from the speakers - obviously it tried to find the LPT dongle.
But there was a crack.

Not sure about Eastern Europe, though. Copyright laws were more lax over there, I guess, so unprotected versions of newer releases might been into circulation.

Depends when - in Poland, current copyright laws are from 1994, and they are about the same as in the entire West, after all they were lobbied for by the western media and software corporations.
Of course, it didn't stop circulation of cracked versions for personal use, but they got mostly excluded from commercial use.

Hardware dongles got more complex

I had multiple proprietary business programs that required an LPT dongles even in the early 2k
Creative Names, Utrecht Software Heraldry, and First Names almanac .
Those places selling signs with letters made of Disney characters had dongles that counted how many you made to charge a refill/copywrite fee.

I actually had 2 dongles until I found a software emulator for windows 98

Sadly both the dongle and emulator didn’t work under Windows XP or beyond (I found a specialized driver that had to be loaded for the dongle to work in xp years after it would have been helpful)

I was working for a software development company that sold a product protected by a USB dongle from 2001 to 2006 😀 and the boxed copy of Propellerhead Reason 4 I bought in 2007 or 2008 also had a USB dongle. They did eventually phase it out some versions later.

In both cases the target was WinXP, and those were my last personal experiences with hardware dongles. But wouldn't be surprised some niche software kept them longer 😀