From:	defaultuser AT domain DOT com
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: This is not a problem but...
Date:	Sun, 28 Jun 1998 07:00:01 -0600
Organization:	Symbios Logic
Lines:	33
Message-ID:	<35963E50.78F62F96@domain.com>
References:	<3593D789 DOT DCC99FC4 AT netrover DOT com>
NNTP-Posting-Host:	ahadleypc.co.symbios.com
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To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Nicolas Blais wrote:

> When I compile my program, and edit my exe file, I can modify all my
> strings used with printf.  I don't want people to do so, is there a
> way
> to conteract this?
>
> Nicolas Blais.

If you take a look at the assembler output it puts the input string from
printf into data blocks of string. Eg.main() {printf("Hello world!"); }

asm
    ...
    mov ax, offset DGROUP:s@
    push ax
    call near ptr _printf
    ...
s@ label byte
    db    'Hello world!'

This is why your string is seen by the world inside the .EXE. So the
trick is code the string initially from the world-- this involves
physically placing coded string in place of "Hello world!" then decode
using a function.
eg.
main() { printf("%s",decode("IrFTfpq#KB"));}

-Andrew

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