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ChessTiger cracked --- the author strikes back?



 
 
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  #1  
Old August 10th 03, 11:39 PM
Christopher
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Default ChessTiger cracked --- the author strikes back?

Hey guys/gals,

I've read on a couple of messageboards that people who play the
cracked version of ChessTiger (illegally pirated and registered) for
Palm OS get an unusual problem. The chess engine plays at the
difficulty level you set it to for most of the game, but then when you
make it to the end of the game (the endgame) the Chess engine
automatically resets your difficulty to EASY MODE. So ChessTiger could
be beating you at a game of chess, but then near the end of the game,
right before you get checkmated, the computer chess engine will start
to sacrifice its Queen, Bishop and other pieces .....making you win
the game in the end! In a way, it totally ruins the game you're
playing since you didn't really earn that win---the chess computer
just gave you the win.

I thought this was interesting when I heard about this --- my theory:
the author somehow put in a mechanism in the game where if it got
cracked by hackers, it'll play a really strong Chess game against you
for the opening and middle game, until you made it to the endgame. I
suppose it's the authors way of getting back at cheap people who don't
want to buy the game.

But of course this is only my theory. Does anyone know if maybe
ChessTiger for Palm OS is just extremely weak in the endgame, and
that's why it would sacrifice every piece it has? Or is it really true
that the author put in a mechanism to thwart piraters? If it is the
latter, then it's an interesting new way for program authors to copy
protect their software....to sabotage the function of the program
without you really knowing it.

-Chris
  #2  
Old August 11th 03, 06:46 AM
Proboscis
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Posts: n/a
Default ChessTiger cracked --- the author strikes back?

Sounds like a cool solution.

The cracker has no way to check whether his crack really works, unless he
plays several games against the program. (And then he still can't be
sure...)

I suspect some pc programs use this strategy as well.

"Tony Clark" schreef in bericht
ink.net...
Sounds a little hokey to me. How would the game know if it's been cracked?
If the game could detect that why not just refuse to play a game in the
first place? Otherwise I don't see the point of haveing a secure game.

TC

"Christopher" wrote in message
om...
Hey guys/gals,

I've read on a couple of messageboards that people who play the
cracked version of ChessTiger (illegally pirated and registered) for
Palm OS get an unusual problem. The chess engine plays at the
difficulty level you set it to for most of the game, but then when you
make it to the end of the game (the endgame) the Chess engine
automatically resets your difficulty to EASY MODE. So ChessTiger could
be beating you at a game of chess, but then near the end of the game,
right before you get checkmated, the computer chess engine will start
to sacrifice its Queen, Bishop and other pieces .....making you win
the game in the end! In a way, it totally ruins the game you're
playing since you didn't really earn that win---the chess computer
just gave you the win.

I thought this was interesting when I heard about this --- my theory:
the author somehow put in a mechanism in the game where if it got
cracked by hackers, it'll play a really strong Chess game against you
for the opening and middle game, until you made it to the endgame. I
suppose it's the authors way of getting back at cheap people who don't
want to buy the game.

But of course this is only my theory. Does anyone know if maybe
ChessTiger for Palm OS is just extremely weak in the endgame, and
that's why it would sacrifice every piece it has? Or is it really true
that the author put in a mechanism to thwart piraters? If it is the
latter, then it's an interesting new way for program authors to copy
protect their software....to sabotage the function of the program
without you really knowing it.

-Chris





  #3  
Old August 11th 03, 07:10 AM
Nonyz
external usenet poster
 
Posts: n/a
Default ChessTiger cracked --- the author strikes back?

There's nothing new or hokey about this kind of a protection scheme. A
program can have a routine that checks it's own CRC [digital
signature] - any tampering would be detected by this routine.

The flip side to this is that if a legitimate owner's program gets
corrupt for some reason, even though this would be detected - he would
not be informed about it, instead he would be similarly 'punished.'

Another thing the programmer could do would be to just exit without
any messages when tampering is detected. This way the legit owner
would be forced to reinstall. However the exit code would be far
easier to detect [and modify] than something hidden deep inside the
chess-playing routine.



"Tony Clark" wrote in message link.net...
Sounds a little hokey to me. How would the game know if it's been cracked?
If the game could detect that why not just refuse to play a game in the
first place? Otherwise I don't see the point of haveing a secure game.

TC

"Christopher" wrote in message
om...
Hey guys/gals,

I've read on a couple of messageboards that people who play the
cracked version of ChessTiger (illegally pirated and registered) for
Palm OS get an unusual problem. The chess engine plays at the
difficulty level you set it to for most of the game, but then when you
make it to the end of the game (the endgame) the Chess engine
automatically resets your difficulty to EASY MODE. So ChessTiger could
be beating you at a game of chess, but then near the end of the game,
right before you get checkmated, the computer chess engine will start
to sacrifice its Queen, Bishop and other pieces .....making you win
the game in the end! In a way, it totally ruins the game you're
playing since you didn't really earn that win---the chess computer
just gave you the win.

I thought this was interesting when I heard about this --- my theory:
the author somehow put in a mechanism in the game where if it got
cracked by hackers, it'll play a really strong Chess game against you
for the opening and middle game, until you made it to the endgame. I
suppose it's the authors way of getting back at cheap people who don't
want to buy the game.

But of course this is only my theory. Does anyone know if maybe
ChessTiger for Palm OS is just extremely weak in the endgame, and
that's why it would sacrifice every piece it has? Or is it really true
that the author put in a mechanism to thwart piraters? If it is the
latter, then it's an interesting new way for program authors to copy
protect their software....to sabotage the function of the program
without you really knowing it.

-Chris

  #4  
Old August 11th 03, 01:18 PM
Traveller
external usenet poster
 
Posts: n/a
Default ChessTiger cracked --- the author strikes back?

Well way is, the program itself can check it's own code (program file)
against a template, hidden as a data file during install. If the program
doesn't match byte for byte the template, it will be able to determine if it
has been cracked or hacked.

Richard

"Tony Clark" wrote in message
ink.net...
Sounds a little hokey to me. How would the game know if it's been cracked?
If the game could detect that why not just refuse to play a game in the
first place? Otherwise I don't see the point of haveing a secure game.

TC

"Christopher" wrote in message
om...
Hey guys/gals,

I've read on a couple of messageboards that people who play the
cracked version of ChessTiger (illegally pirated and registered) for
Palm OS get an unusual problem. The chess engine plays at the
difficulty level you set it to for most of the game, but then when you
make it to the end of the game (the endgame) the Chess engine
automatically resets your difficulty to EASY MODE. So ChessTiger could
be beating you at a game of chess, but then near the end of the game,
right before you get checkmated, the computer chess engine will start
to sacrifice its Queen, Bishop and other pieces .....making you win
the game in the end! In a way, it totally ruins the game you're
playing since you didn't really earn that win---the chess computer
just gave you the win.

I thought this was interesting when I heard about this --- my theory:
the author somehow put in a mechanism in the game where if it got
cracked by hackers, it'll play a really strong Chess game against you
for the opening and middle game, until you made it to the endgame. I
suppose it's the authors way of getting back at cheap people who don't
want to buy the game.

But of course this is only my theory. Does anyone know if maybe
ChessTiger for Palm OS is just extremely weak in the endgame, and
that's why it would sacrifice every piece it has? Or is it really true
that the author put in a mechanism to thwart piraters? If it is the
latter, then it's an interesting new way for program authors to copy
protect their software....to sabotage the function of the program
without you really knowing it.

-Chris





  #5  
Old August 11th 03, 05:16 PM
Ron Larham
external usenet poster
 
Posts: n/a
Default ChessTiger cracked --- the author strikes back?

(Christopher) wrote in message . com...
Hey guys/gals,

I've read on a couple of messageboards that people who play the
cracked version of ChessTiger (illegally pirated and registered) for
Palm OS get an unusual problem. The chess engine plays at the
difficulty level you set it to for most of the game, but then when you
make it to the end of the game (the endgame) the Chess engine
automatically resets your difficulty to EASY MODE. So ChessTiger could
be beating you at a game of chess, but then near the end of the game,
right before you get checkmated, the computer chess engine will start
to sacrifice its Queen, Bishop and other pieces .....making you win
the game in the end! In a way, it totally ruins the game you're
playing since you didn't really earn that win---the chess computer
just gave you the win.


This is the normal behaviour of an _unregistered_ copy.


I thought this was interesting when I heard about this --- my theory:
the author somehow put in a mechanism in the game where if it got
cracked by hackers, it'll play a really strong Chess game against you
for the opening and middle game, until you made it to the endgame. I
suppose it's the authors way of getting back at cheap people who don't
want to buy the game.

But of course this is only my theory. Does anyone know if maybe
ChessTiger for Palm OS is just extremely weak in the endgame, and
that's why it would sacrifice every piece it has? Or is it really true
that the author put in a mechanism to thwart piraters? If it is the
latter, then it's an interesting new way for program authors to copy
protect their software....to sabotage the function of the program
without you really knowing it.

-Chris

  #6  
Old August 11th 03, 11:15 PM
Stan Moore
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Posts: n/a
Default ChessTiger cracked --- the author strikes back?

wlcna wrote:
"Nonyz" wrote in message
om...
There's nothing new or hokey about this kind of a protection scheme. A
program can have a routine that checks it's own CRC [digital
signature] - any tampering would be detected by this routine.


Yeah, but that's not the point.

Are you saying the CRC it's comparing to can't be hacked as well?

TC is right, in order to say that the program has actually been "cracked"
all these mechanisms would have to have been defeated. If they haven't,
then the program has never been successfully cracked, by definition.


Actually it's relatively easy to work through a program start up and get
past most copy protection. Technically CRC is relatively hard to crack,
but fortunately it's not hard to just fix the test so it always passes
and bypasses the CRC altogether. On the other hand burying the test in
code that happens after start up can make it MUCH harder to find the
test and therefore harder to bypass. So it's technically feasible that it
would be relatively easy to crack the start up and not be able to easily
crack any checks that happen after startup.

For the record I don't do cracks, but I have debugged many a program,
including assembly programs, and I'm familiar with the tools to step
through a program.

--
Support your Coast Guard - get lost.
  #7  
Old August 12th 03, 07:09 AM
Nonyz
external usenet poster
 
Posts: n/a
Default ChessTiger cracked --- the author strikes back?

Stan Moore wrote in message ...

Actually it's relatively easy to work through a program start up and get
past most copy protection.
Technically CRC is relatively hard to crack,
but fortunately it's not hard to just fix the test so it always passes
and bypasses the CRC altogether. On the other hand burying the test in
code that happens after start up can make it MUCH harder to find the
test and therefore harder to bypass. So it's technically feasible that it
would be relatively easy to crack the start up and not be able to easily
crack any checks that happen after startup.


IMNSHO, it does not matter so much where the test is placed. What
really matters however is how the program reacts when it detects
something amiss. For example, a few programs I've seen were smart
enough to test their own CRC, but they goofed up terribly coz the user
was informed with a messagebox immediately after the CRC test about
the 'CRC failure.' All the cracker had to do was break on this
messagebox and he had the CRC test code right before him, all that
needed to be done then was to change the flow of the program so no
matter what the CRC was, the test was always passed.

Having said that, coding the security bit within say, the chess
playing code (as was the case with 'The King') makes it tougher to
crack just coz you have to wade through so much irrelevant stuff
before you encounter anything of 'significance.' But a silent security
check right at the start up of the program would be almost as
effective.

For the record I _have_ cracked programs and don't care to (& can't
afford to) take any kind of moral high ground.
  #8  
Old August 14th 03, 12:43 AM
Herbert Kanner
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Posts: n/a
Default ChessTiger cracked --- the author strikes back?

In article c.com,
Jeffrey Kaplan wrote:

Previously on comp.sys.palmtops.pilot, Tony Clark said:

; Sounds a little hokey to me. How would the game know if it's been cracked?
; If the game could detect that why not just refuse to play a game in the
; first place? Otherwise I don't see the point of haveing a secure game.

Things like that have been done before. In DateBk, every so often
someone will ask about some weird fatal error that no one else can
replicate. Every time it turns out that the user was using a cracked
copy, and going legit solved the problem.

Of course, the developer never admits this is on purpose.

I think it's an excellent idea.


However, it's worth mentioning that Chess Tiger shows weakness in some
standard end games. I own both Chess Tiger and Chess Genius for the
Palm. I can't dispute that many have found, by matching them against
each other, that Tiger is the stronger. But, despite Tiger's use of a
transposition table, Tiger goes around in circles on some standard end
games such as K B B vs K and K B N vs K, while Genius proceeds very
directly to a mate. It may be that Genius has built in specific
algorithms for those end games.

Herb

P.S. I find the plethora of display option of Tiger somewhat annoying.
I'm a lousy enough chess player that Genius is plenty good for me and I
just prefer its display simplicity.

--
To send me email, replace deadspam.com by acm.org
 




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