What do you say about this protection ?

Since I don't read French, I am commenting on the apparent function of the Pascal code in your link.

While the use of an external file can/does provide a long encryption key (relative to the data to be encoded), you have provided the key for some user to decrypt the file.

You would have better/stronger encryption to seed the Delphi random number generator in both the encryptor and decryptor routines and use the resulting values to protect your data.

ginsonic,

What do you have in mind?
Can you do some translation for us?

======================================
Did you hear about the Sony CD protection scheme that could be circumvented by blackening the outside edge with a felt-tip marker?  Needless to say, the protection was a joke and the CD player never made it to store shelves in America.  Neither Sony nor the music industry vendors were amused.

inthe, how can be copyed a corupted file ?

ginsonic

No matter what TYPE of protection you use because at the end of the day you will have some lines of code that will compare a value of Registered or Not etc etc and that is easy to crack e.g.


:00403B85 8B4DE8                  mov ecx, dword ptr [ebp-18]
:00403B88 3B4D08                  cmp ecx, dword ptr [ebp+08]
:00403B8B 0F8387010000            jne 00403D18

All that has to be done is patch the jump or the memory address on startup.

Or in the instance of the code you suggest is that you patch the return val e.g.

:00403DA4 8BE5                    mov esp, ebp
:00403DA6 5D                      pop ebp
:00403DA7 C20400                  ret 0004

you just put ....

:00403DA4 8BE5                    mov ebp, 01
:00403DA6 5D                      pop ebp
:00403DA7 C20400                  ret 0004

I have looked into this a lot and theres not much you can do. My 2 pence
Regards
Smurff

You cannot protect the data on a cd unless you control the hardware it runs on.. ala DIVX at Circuit City



It's all a numbers game in real life anyway... a certain percentage of people will bootleg your program... lets say that 10,000 people will eventually pirate your app if you don't protect it at all.. well maybe 9000 of them are such cheap @#$%'s that they would NEVER buy it even if it only cost a nickle... so you can't possible lose anything on them anyway... so let them pirate it... what difference can if make?  and maybe they will praise the software to their friends and a few might actually buy it :-)

Of the 1000 that are left that would actually buy your app if it were not already being passed around all the warez groups maybe 900 would give up and buy it if you put a lot of simple protection schemes in it that popped up randomly... a hacker will find the first one and crack that... then upload it to alt.binaries.warez.im-so-smart
and then move on to crack the next application he comes across... and then a few week or months later the pirated software starts to fail when your 2nd piece of protection code kicks in... many of the pirates will now like your app so much that maybe they will buy it... after all.. they are using it everyday and the crack failed..and now they depend on it :-)


p.s. Just make the first protection scheme real easy to crack... that way you draw in more pirates quicker... and when the crack fails you may have many eager buyers ;-)

Oh!
Perhaps the saddest thing that can happen is that your program is so lame that nobody even bothers to crack it and upload it to the warez groups... imagine if nobody wanted your stuff... even for free :-/

I remember my first two components . I found these thanks to hazard ( I received a message from a warez group with a cracks list ). Just one week after release.

And I wish to say that I was glad to find my components on list :)

Are you writing a component or an application?  If you want to protect an application, you should look at some of the "wrapping" technologies.  I use one from Bit-Arts.

>> how can be copyed a corupted file ?

via "bit" copying ,files are irrelevent at bit level.
nero etc shouldnt have a problem doing it.

Thanks to all for support,
Nick