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Conference hydra::amiga_v1

Title:AMIGA NOTES
Notice:Join us in the *NEW* conference - HYDRA::AMIGA_V2
Moderator:HYDRA::MOORE
Created:Sat Apr 26 1986
Last Modified:Wed Feb 05 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:5378
Total number of notes:38326

2305.0. "Copy Protection" by DECWET::TBAKER (Tom Baker - DECwest CSSE) Wed Mar 01 1989 21:52

    2289.5 asked an interesting question:
    
>    13. How is copy protection of commercial disks achieved ? I can't
>       figure how this is done . Surely if you can read a disk you
>       can copy it ?
    
    I don't think it's been discussed before in this conference so I
    thought it deserved its own note. I'd be interested in any technical
    discussions of specific copy protection schemes. Any experts on copy
    protection out there? 
    
    I've heard one method is to make certain blocks 'bad'. A normal copy
    program will ignore bad blocks but code could be inserted in the
    protected program to check certain physical blocks on the disk.
    
    Following is one copy protection method posted by Rob Peck to
    comp.sys.amiga.tech.
    
    tom
    				----------------
    

The one copy protection scheme that I don't believe can be broken for a
standard Amiga to be used as a raw track copier is based on the syncing
ability of the Paula chip (I believe this is the correct one...).  The
disk read circuitry can synchronize to a faster bit rate than, under
actual clock control, it can write.  Thus if the standard number of
sectors on a track is 11, as I recall by writing the disk on a special
machine with a faster bit rate than the Amiga, one could squeeze 12
sectors, formatted normally so to speak, on the same track.  The Amiga
could sync to this higher rate, but using a standard clock, like "Joe Breaker"
has in his machine, it would be possible to READ this data, but not
enough room on the disk to WRITE it out again for the copy in a single
revolution.  Thus unless the program code was hacked as well, this
would make it a lot harder to break and impossible on a standard
machine to copy.  (My exposure to Amy hardware is over 2 years old,
so I might not be correct, but this is something I recall from some
time past).

I don't know about any other schemes, but this one always impressed me
as pretty good.

Rob Peck


    
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2305.1A fair system of protection...NZOV01::MCKENZIENuke the Leprechaun!Thu Mar 02 1989 15:2015
    One onf the most novel protection systems Ive seen is that used
    by Magnetic scrolls in their games, "The Pawn" and "The Guild of Thieves"
    
    There is NO copy protection on the actual disk, but the game object
    is compiled with a full "dictionary" type file containing every
    word in the booklet that comes with the game. Periodiclly (I suspect
    when a random number is drawn) the game pauses and asks the player
    to turn to page x,column x , line x, word x and type the word. The
    user gets three chances to get it correct - if the correct word is
    not entered on the 3rd attempt the game stops.
    
    Now....You all might think "SO - JUST COPY THE MANUAL" but think
    
    when was the last time you saw a pirated game WITH documentation??
        
2305.2I'd never buy from people who use this method!!NZOV01::MCKENZIENuke the Leprechaun!Thu Mar 02 1989 15:237
    The nastiest protection scheme would have to be that used by the
    people who make "Winter Olympics" - a reliable source has informed
    me that attempts to copy this disk result in a Virus, hidden on
    the source disk to be copied to the boot block of the copied disk
    AND THE SOURCE, if the source is not write-protected.
    
    The Virus, from all accounts seems to be the BYTE BANDIT Virus
2305.3My impressions...NZOV01::MCKENZIENuke the Leprechaun!Thu Mar 02 1989 15:5445
    Ok  sportsfans! heres an item that might interest you...
    
    For years the "viscious-circle" syndrome involving copy-protection
    schemes has been battled out!
    
    Software Developers claim that Pirates are the reason for
    copy-protection schemes and the high software prices! Software
    developers say that if everyone honestly purchased their products
    the prices would come down....
    
    Pirates claim That the reason they pirate software is that its so
    damn expensive to purchase. (I tend to support this argument - I
    would have NO qualms about spending $30 on a game but $120 to me
    just aint worth it!) Pirates say that when software prices are reduced
    to what the general consumer would regard as reasonable then Pirating
    will stop - It's a simply matter of economics. Why spend
    X+++ hours cracking a disk that you could buy for around $30?
    
    When I look at how this circle has evolved (developers writing smarter
    protection schemes - hackers/pirates cracking them) I realise that
    the only people REALLY making money are those who write the fancy
    copy programmes to beat the "protection racket" (no pun intended)
    
    Developer have even had the gall to blame prices on import
    duties/retail markups etc etc etc...while this is partially
    true its not the whole truth by any stretch of the imagination!
    
    But the final circle-breaking proof is this; Last year a software
    retailer near where my Father lives in Tauranga,New Zealand was
    stocking games for the Amiga at $25 each. AND HE COULD NOT KEEP
    UP WITH THE DEMAND FOR THESE GAMES. The games on his shelves that
    were around the $100 mark are still there - or so I'm told!
    
    So thats it - The day developers start being realistic is the day
    they will stop the bulk of the pirating trade.
    
    Comments folks??
    
    Phil
    
    
    
    
    
    
2305.4LEDS::ACCIARDIThu Mar 02 1989 18:1225
    
    I've personally seen a few cases where a developer deliberately ships
    a buggy product because they desperately need money to continue
    work.  I find this practice abhorrent.  I remember plunking down
    $90 for ProWrite 1.0 and rushing home, delighted to finally have
    a decent WP for the Amiga.  
    
    Within 1 minute of starting the program, I was treated to several
    fatal crashes.  The bugs were so obvious that if the software
    had been beta tested for even 30 seconds the errors would have been
    spotted. 
    
    The fact that ProWrite is NOW a fine product does little to erase
    my animosity.  Imagine if a car dealer expected you to wait six
    months for your new car (for which you already paid) to work properly?
    
    What does all this have to do with piracy?  Perry Kivolowitz of
    ASDG long ago proposed a contract between software developers and
    users.  The contract was a guaranty that the Seller would provide
    quality, bug-free software that performed as advertised.  The Buyer
    would agree to pay for said software.  As far as I know, not much
    progress has been made on the first, ie, PageStream.
                   
    Ed.
    
2305.5DECWET::TBAKERTom Baker - DECwest CSSEThu Mar 02 1989 20:509
    I'm still interested in technical explanations of hard copy protection
    schemes (disks that can't be copied). How do you make a disk that can
    be read and booted but not copied - even by a physical byte for byte
    copy program. There must be many different methods because Marauder
    had to be continually upgraded for new programs (before they decided
    there was more profit in copy protected games). Has anyone seen any
    articles written about copy protection?
    
    tom
2305.6BCSE::LIMBERTThe Night Belongs to Anchor Steam.Fri Mar 03 1989 09:5519
      It's pretty easy to make a disk so it can't be copied with normal
    operating system commands. Protecting a disk against a 'bit copier'
    (which bypasses the OS and talks directly to the hardware) is harder
    and usually involves either 
       
       (a) taking advantage of the fact the most disk controllers and drives 
           are capable of reading things which they can't write. For
           example, if a diskette is written while rotating at a slower
           than standard speed, more data can be squeezed onto it. A normal
           speed drive will be able to read this extra data, but probably 
           won't be able to write it out to another disk.
    
       (b) physically altering the disk in some way. Some methods burn a 
           small hole in the disk with a laser. Obviously, no copier can
           reproduce this.
    
      An issue of PC Tech Journal from late (maybe December?) 1985 had a good 
    article on the subject. It deals with IBM-style PCs, but the methods are 
    pretty generic.
2305.7BAGELS::BRANNONDave BrannonFri Mar 03 1989 12:2012
    another trick is to write more tracks on the disk.  This scheme
    is/was popular in the ST market, but... the disk drive makers
    only guarantee that the drive can read 80 tracks, not 81-85.
    So there is a distinct possibility that the scheme will fail
    on a number of customer systems.
    
    The flexibility of the software design of the Amiga disk controller
    means it can read/write things that an ibmpc disk controller can't.
    It also means that the copy protection writers have lots of flexibility
    in what they can do to a disk format.
    
    -Dave
2305.8For more info see...R2ME2::MULLENDan Mullen, Run-Time Libraries.Fri Mar 03 1989 18:345
A mid 1986 issue of IEEE spectrum (which should be available in some form at all
DEC libraries) covered some copy protection methods.  This issue also discused
and compared some PC's.  The Amiga was one of them I'm happy to say.

..Dan
2305.9Abacus book - $30BOMBE::MOORESo many holes to plugFri Mar 03 1989 19:082
    Abacus publishes "Amiga Disk Drives - Inside & Out".  I haven't looked
    at it, but their ad claims it discusses copy protection schemes, etc.