6 ms·

Atari Centipede’s Hidden Code Trap

120 points by jasoneckert 7y ago

mordechai9000 7y ago
So how was the code trap implemented?
- deleted 7y ago
  [deleted]
- bagels 7y ago
  Sounds like a coded message in the rom dump
  - WarOnPrivacy 7y ago
    That's where but not how. "This trap consists of a particular data pattern. Only with the help of special code is it possible to read this pattern." This is the key part of the story & it's totally unexplained. The blogger "Tony" just dropped it in there with no vetting at all, as if the method was self evident. Such is news in the new millennia. The claim could just be bullcrap. Atari would have known that courts are tech-illiterate and the defendant might not have shown up for the hearings.
    - videotopia 7y ago
      Well to be fair, all there is to go on at this point is that document. The blog is pitched at a wide audience and is meant to be a "light" entertaining read, rather than something in depth and technical. But agreed, it would be interesting to know the exact process of "extracting" the coded message. The point of the article is that it was there (or to your point, it was claimed in court that it was there!), rather than how it got there. Bottom line - it did the trick.
      - daveFNbuck 7y ago
        Ed Logg is alive today according to his Wikipedia entry, so there's more to go on if someone wants to do write something more detailed about this incident.
- umvi 7y ago
  Sounded like steganography... Encoding Morse code into unused bits in the ROM
- 13of40 7y ago
  A little bit of googling shows the ROM is available. Might be a good weekend project to bust out your disassembler and find out...
- sehugg 7y ago
  Yeah, I don’t get it. You could just compare the ROMs directly. I can XOR any arbitrary secret message with a long enough key.
  - kbsletten 7y ago
    From the article, it wasn't a XOR, the "key" was that there was a bit sequence when interpreted as Morse code said something like "copyright ATARI". So, reasonably easy to show it wasn't just pulling the message out of thin air.
  - pkaye 7y ago
    The ROMs wouldn't an exact match so you have to convince the layman jury that the differences are meaningful. The best way it to show something totally unexpected in the pirated code like your own copyright.
- kabdib 7y ago
  I wrote a few game cartridges for the Atari 400/800 computers when I was there in the early 80s. We were told to include a specific bit pattern, I think it was 5 or 8 bytes long, somewhere in our code. The idea was that the presence of a non-functional, unique bit pattern was going to be very difficult for a defendant to explain in court, since pirates mostly just copied ROMs and made minimal changes to obvious bitmaps and strings. Even if they found the mysterious bit pattern and were clever enough to (say) zero it out, they'd have to explain why most of a ROM was identical except for visible assets and that one set of bytes with no function ("What are these bytes for? Oh, you don't know? Let us show you...") We weren't told what the pattern meant. I played with it for a couple of hours once; I knew it wasn't executable 6502 code or simple logical bit operation (NOT, reverse bits, etc.) of anything obvious. Morse code makes sense now. Some coinop machines (Tempest, for sure) used character encodings so that the visible copyright messages were also executable code; changing the message, even slightly, would crash or have unpredictable behavior. In the case of Tempest, when the "final" ROMs were released to manufacturing, the dev team went on vacation while production ramped up. Some lawyer decided that the copyright message had to change, so they patched the ROM on the factory floor. Unfortunately this modification didn't lead to an immediate crash, but opened up a hole where the contents of the score line could do things like give you 100 extra lives (e.g., die with the low digits of your score being "50" and you'd be able to play for free for hours).
  - i_am_nomad 7y ago
    Side note here, the Atari 800 was my first computer, and I absolutely loved every minute of it. Thanks for all your work and ingenuity, they gave me a good start on a career in technology. One question: why didn’t the Atari 800 ever take advantage of the double cartridge ports?
    - kabdib 7y ago
      My understanding was that the second cartridge slot was not a very well thought out thing. I think there was one cartridge made for it (some debugging tool?) That port cost a lot of money per unit; Atari's early efforts were not very well cost reduced. If they'd been more aggressive about cost reductions (and improving I/O speeds) they might have done much better in the market against Commodore. Instead we got more unclear hardware directions (the 1200XL's "Help" key was a prime example of the hardware group just not caring about or talking to the software folks), even more expensive machines, and a bunch of work being done by outside contractors instead of inside staff because it was easier to build empires that way. The 7200 game machine (developed by General Computer Corporation in Cambridge, IIRC) was a surprise to most of us, for instance, and not a good one.
jeffrallen 7y ago
Xor ftw!
emptybits 7y ago
The article tells us the non-Atari game retained a damning Morse message in its ROM. From another source[1] (unverified), this may be the ROM data the article refers to: .BYTE 2, 0BB, 5A, 30 (where 0 is dot and 1 is dash and nothing for a space) .BYTE 5F, 0EE, 7D, 0A8 ; Morse code for "COPYRIGHT 1980 ATARI" [1] https://www.binarni.net/2013/07/centipede/ https://www.binarni.net/2013/07/centipede/ With all the ROM images floating around in the MAME/retro scene, someone can probably verify this.
- emptybits 7y ago
  Okay, replying to my own curiosity... The above byte sequence can be found in a dump of Centipede's ROM. 00001280 a2 13 a9 ab 5d 20 21 ca 10 fa 85 fe 60 02 bb 5a |....] !.....`..Z| 00001290 30 5f ee 7d a8 20 b3 21 85 ae b9 c0 21 85 b0 a9 |0_.}. .!....!...| The entire arcade game is contained in 12 kilobytes of code, BTW. (!) The amount of imagination and fun and replayability that this era of gaming delivered under such constraints (by modern luxurious standards) is mind boggling.
  - mypalmike 7y ago
    Spent a little time decoding this... 02 BB 5A 30 5F EE 7D A8 00000010 10111011 01011010 00110000 01011111 11101110 01111101 10101000 C. ..O..P.. .Y...R.. I.G..H.. .T1....9 ....8... .0....A. TA.R..I. *edit: formatting
    - stonic 7y ago
      Did you use the source code for this?
      - mypalmike 7y ago
        Nah, I just did a little manual pattern-matching on the bits looking for "ATARI" (morse code : "0110101000") and working backwards from there.
  - 7y ago
Amorymeltzer 7y ago
>Simply stating that "this game copied our idea!" is all well and good; but in a court of law, the case has to be proven beyond any reasonable doubt. In common law systems such as the US and Canada, "beyond a reasonable doubt" is generally the metric used for criminal law. Civil cases, such as this, generally use preponderance of evidence; it's a much weaker standard, essentially meaning that whichever side is more than 50% supported by the evidence will win. Doesn't take away from the interest in this code trap, but Atari did have a lower bar for success.
- geofft 7y ago
  Wouldn't this have been criminal copyright infringement, since it was for commercial gain and impacting the commercial prospects of Atari?
  - Amorymeltzer 7y ago
    IANAL (or an expert on Canadian IP law) but while it perhaps could have been as well, it's pretty clear from TFA that this was a civil lawsuit. Use of the term "lawsuit" and "plaintiff" (the latter in the only actual document provided[1]) are dead giveaways, as is the fact that the government (who prosecutes criminal cases) does not appear to be involved. 1: https://missilecommand.files.wordpress.com/2018/12/ilovepdf_merged.pdf https://missilecommand.files.wordpress.com/2018/12/ilovepdf_...
vessenes 7y ago
It would have been really rad to tie this embedded message to an input sequence. I guess in centipede that’s extra hard, but it would make for a great moment in court when the devs roll in defendants machine and moments later copyright Atari shows up..
- joezydeco 7y ago
  Jarvis and DeMar did exactly this on Robotron:2084, in the hopes it would be useful in court one day: https://youtu.be/3zr4CdUdt0w https://youtu.be/3zr4CdUdt0w
Vivtek 7y ago
Ha! This makes Rap Genius's apostrophe trap even more delightful, then. https://www.rollingstone.com/music/music-news/genius-google-stole-lyrics-morse-code-848781/ https://www.rollingstone.com/music/music-news/genius-google-...
corysama 7y ago
A similar technique was used to prove that the mobile game Heroes Charge was built on stolen code https://www.facebook.com/allstarheroes.en/videos/1577087785877567/ https://www.facebook.com/allstarheroes.en/videos/15770877858... Except that code has become a lot more complicated since the Atari days. So, you don't need a hex dump to show the evidence. Just a gesture sequence on a certain screen and the UI pops up "Copyright: The Original Company". Meanwhile, the original company was simultaneously being sued by Blizzard for blatantly knocking off the character designs of World of Warcraft https://blizzardwatch.com/2015/03/24/blizzard-files-lawsuit-against-lilith-games-for-copyright-infringement/ https://blizzardwatch.com/2015/03/24/blizzard-files-lawsuit-...
Someone 7y ago
Similar to https://www.folklore.org/StoryView.py?story=Stolen_From_Apple.txt https://www.folklore.org/StoryView.py?story=Stolen_From_Appl...: ”Steve decided that if a company copied the Mac ROM into their computer, he would like to be able to do a demo during the trial, where he could type a few keystokes into an unmodified infringing machine, and have a large "Stolen From Apple" icon appear on its screen.”
praptak 7y ago
>Simply stating that "this game copied our idea!" is all well and good; but in a court of law, the case has to be proven beyond any reasonable doubt. This sounds like patents or copyrights can grant monopoly on an idea. As far as I know, this is not the case. (Well, at least not in principle.)
yitchelle 7y ago
This reminds of the story why Van Halen had a M&M clause in their contract for rock concerts. It is a trap to ensure that the contract was fully read and complied with. https://www.snopes.com/fact-check/brown-out/ https://www.snopes.com/fact-check/brown-out/

120 points by jasoneckert 7y ago

mordechai9000 7y ago

So how was the code trap implemented?

deleted 7y ago
[deleted]
bagels 7y ago
Sounds like a coded message in the rom dump
- WarOnPrivacy 7y ago
  That's where but not how. "This trap consists of a particular data pattern. Only with the help of special code is it possible to read this pattern." This is the key part of the story & it's totally unexplained. The blogger "Tony" just dropped it in there with no vetting at all, as if the method was self evident. Such is news in the new millennia. The claim could just be bullcrap. Atari would have known that courts are tech-illiterate and the defendant might not have shown up for the hearings.
  - videotopia 7y ago
    Well to be fair, all there is to go on at this point is that document. The blog is pitched at a wide audience and is meant to be a "light" entertaining read, rather than something in depth and technical. But agreed, it would be interesting to know the exact process of "extracting" the coded message. The point of the article is that it was there (or to your point, it was claimed in court that it was there!), rather than how it got there. Bottom line - it did the trick.
    - daveFNbuck 7y ago
      Ed Logg is alive today according to his Wikipedia entry, so there's more to go on if someone wants to do write something more detailed about this incident.
umvi 7y ago
Sounded like steganography... Encoding Morse code into unused bits in the ROM
13of40 7y ago
A little bit of googling shows the ROM is available. Might be a good weekend project to bust out your disassembler and find out...
sehugg 7y ago
Yeah, I don’t get it. You could just compare the ROMs directly. I can XOR any arbitrary secret message with a long enough key.
- kbsletten 7y ago
  From the article, it wasn't a XOR, the "key" was that there was a bit sequence when interpreted as Morse code said something like "copyright ATARI". So, reasonably easy to show it wasn't just pulling the message out of thin air.
- pkaye 7y ago
  The ROMs wouldn't an exact match so you have to convince the layman jury that the differences are meaningful. The best way it to show something totally unexpected in the pirated code like your own copyright.
kabdib 7y ago
I wrote a few game cartridges for the Atari 400/800 computers when I was there in the early 80s. We were told to include a specific bit pattern, I think it was 5 or 8 bytes long, somewhere in our code. The idea was that the presence of a non-functional, unique bit pattern was going to be very difficult for a defendant to explain in court, since pirates mostly just copied ROMs and made minimal changes to obvious bitmaps and strings. Even if they found the mysterious bit pattern and were clever enough to (say) zero it out, they'd have to explain why most of a ROM was identical except for visible assets and that one set of bytes with no function ("What are these bytes for? Oh, you don't know? Let us show you...") We weren't told what the pattern meant. I played with it for a couple of hours once; I knew it wasn't executable 6502 code or simple logical bit operation (NOT, reverse bits, etc.) of anything obvious. Morse code makes sense now. Some coinop machines (Tempest, for sure) used character encodings so that the visible copyright messages were also executable code; changing the message, even slightly, would crash or have unpredictable behavior. In the case of Tempest, when the "final" ROMs were released to manufacturing, the dev team went on vacation while production ramped up. Some lawyer decided that the copyright message had to change, so they patched the ROM on the factory floor. Unfortunately this modification didn't lead to an immediate crash, but opened up a hole where the contents of the score line could do things like give you 100 extra lives (e.g., die with the low digits of your score being "50" and you'd be able to play for free for hours).
- i_am_nomad 7y ago
  Side note here, the Atari 800 was my first computer, and I absolutely loved every minute of it. Thanks for all your work and ingenuity, they gave me a good start on a career in technology. One question: why didn’t the Atari 800 ever take advantage of the double cartridge ports?
  - kabdib 7y ago
    My understanding was that the second cartridge slot was not a very well thought out thing. I think there was one cartridge made for it (some debugging tool?) That port cost a lot of money per unit; Atari's early efforts were not very well cost reduced. If they'd been more aggressive about cost reductions (and improving I/O speeds) they might have done much better in the market against Commodore. Instead we got more unclear hardware directions (the 1200XL's "Help" key was a prime example of the hardware group just not caring about or talking to the software folks), even more expensive machines, and a bunch of work being done by outside contractors instead of inside staff because it was easier to build empires that way. The 7200 game machine (developed by General Computer Corporation in Cambridge, IIRC) was a surprise to most of us, for instance, and not a good one.

jeffrallen 7y ago

Xor ftw!

emptybits 7y ago

The article tells us the non-Atari game retained a damning Morse message in its ROM. From another source[1] (unverified), this may be the ROM data the article refers to: .BYTE 2, 0BB, 5A, 30 (where 0 is dot and 1 is dash and nothing for a space) .BYTE 5F, 0EE, 7D, 0A8 ; Morse code for "COPYRIGHT 1980 ATARI" [1] https://www.binarni.net/2013/07/centipede/ https://www.binarni.net/2013/07/centipede/ With all the ROM images floating around in the MAME/retro scene, someone can probably verify this.

emptybits 7y ago
Okay, replying to my own curiosity... The above byte sequence can be found in a dump of Centipede's ROM. 00001280 a2 13 a9 ab 5d 20 21 ca 10 fa 85 fe 60 02 bb 5a |....] !.....`..Z| 00001290 30 5f ee 7d a8 20 b3 21 85 ae b9 c0 21 85 b0 a9 |0_.}. .!....!...| The entire arcade game is contained in 12 kilobytes of code, BTW. (!) The amount of imagination and fun and replayability that this era of gaming delivered under such constraints (by modern luxurious standards) is mind boggling.
- mypalmike 7y ago
  Spent a little time decoding this... 02 BB 5A 30 5F EE 7D A8 00000010 10111011 01011010 00110000 01011111 11101110 01111101 10101000 C. ..O..P.. .Y...R.. I.G..H.. .T1....9 ....8... .0....A. TA.R..I. *edit: formatting
  - stonic 7y ago
    Did you use the source code for this?
    - mypalmike 7y ago
      Nah, I just did a little manual pattern-matching on the bits looking for "ATARI" (morse code : "0110101000") and working backwards from there.
- 7y ago

Amorymeltzer 7y ago

>Simply stating that "this game copied our idea!" is all well and good; but in a court of law, the case has to be proven beyond any reasonable doubt. In common law systems such as the US and Canada, "beyond a reasonable doubt" is generally the metric used for criminal law. Civil cases, such as this, generally use preponderance of evidence; it's a much weaker standard, essentially meaning that whichever side is more than 50% supported by the evidence will win. Doesn't take away from the interest in this code trap, but Atari did have a lower bar for success.

geofft 7y ago
Wouldn't this have been criminal copyright infringement, since it was for commercial gain and impacting the commercial prospects of Atari?
- Amorymeltzer 7y ago
  IANAL (or an expert on Canadian IP law) but while it perhaps could have been as well, it's pretty clear from TFA that this was a civil lawsuit. Use of the term "lawsuit" and "plaintiff" (the latter in the only actual document provided[1]) are dead giveaways, as is the fact that the government (who prosecutes criminal cases) does not appear to be involved. 1: https://missilecommand.files.wordpress.com/2018/12/ilovepdf_merged.pdf https://missilecommand.files.wordpress.com/2018/12/ilovepdf_...

vessenes 7y ago

It would have been really rad to tie this embedded message to an input sequence. I guess in centipede that’s extra hard, but it would make for a great moment in court when the devs roll in defendants machine and moments later copyright Atari shows up..

joezydeco 7y ago
Jarvis and DeMar did exactly this on Robotron:2084, in the hopes it would be useful in court one day: https://youtu.be/3zr4CdUdt0w https://youtu.be/3zr4CdUdt0w

Vivtek 7y ago

Ha! This makes Rap Genius's apostrophe trap even more delightful, then. https://www.rollingstone.com/music/music-news/genius-google-stole-lyrics-morse-code-848781/ https://www.rollingstone.com/music/music-news/genius-google-...

corysama 7y ago

A similar technique was used to prove that the mobile game Heroes Charge was built on stolen code https://www.facebook.com/allstarheroes.en/videos/1577087785877567/ https://www.facebook.com/allstarheroes.en/videos/15770877858... Except that code has become a lot more complicated since the Atari days. So, you don't need a hex dump to show the evidence. Just a gesture sequence on a certain screen and the UI pops up "Copyright: The Original Company". Meanwhile, the original company was simultaneously being sued by Blizzard for blatantly knocking off the character designs of World of Warcraft https://blizzardwatch.com/2015/03/24/blizzard-files-lawsuit-against-lilith-games-for-copyright-infringement/ https://blizzardwatch.com/2015/03/24/blizzard-files-lawsuit-...

Someone 7y ago

Similar to https://www.folklore.org/StoryView.py?story=Stolen_From_Apple.txt https://www.folklore.org/StoryView.py?story=Stolen_From_Appl...: ”Steve decided that if a company copied the Mac ROM into their computer, he would like to be able to do a demo during the trial, where he could type a few keystokes into an unmodified infringing machine, and have a large "Stolen From Apple" icon appear on its screen.”

praptak 7y ago

>Simply stating that "this game copied our idea!" is all well and good; but in a court of law, the case has to be proven beyond any reasonable doubt. This sounds like patents or copyrights can grant monopoly on an idea. As far as I know, this is not the case. (Well, at least not in principle.)

yitchelle 7y ago

This reminds of the story why Van Halen had a M&M clause in their contract for rock concerts. It is a trap to ensure that the contract was fully read and complied with. https://www.snopes.com/fact-check/brown-out/ https://www.snopes.com/fact-check/brown-out/