All,

We've had a few threads over at Foxite looking at VFP protection schemes. This week a protected app was cracked to source in minutes; previously Leonid Lepin was able to lift a key out of three other protection products with no trouble at all.

Having taken a particular interest I'd suggest that few protection schemes out there can protect a VFP app for more than a few minutes.

Anybody is welcome to post a sample of their preferred protection scheme to see whether anybody can crack it. Please use a free dbf as that saves a lot of time to prove the point.

The most effective protection scheme I can find comes from here: http://www.baiyujia.com/f_download.asp ,download VFP Compiler demo. The download includes English instructions. Basically the product splits a VFP project into a VFP exe with no useful content and a C++ dll containing heavily obfuscated, decomposed and distorted instructions that are fearfully difficult to piece back into a VFP project, unlike most other schemes from which it is easy to extract a complete VFP project.

If I'm wrong I'd be delighted if somebody would show me- I'd rather go back to the drawing board than cruise along believing my work is protected when it's wide open.

FWIW, here is the entire source I can extract from one of my own VFP compiler apps: as you can see, I don't need to waste time trying to prevent somebody grabbing this because it's not useful: a hacker now needs to disassemble the associated dll or at least trap a plethora of VFP runtime calls hoping to splice something useful out if it.

IF FILE(LEFT(_VFP.SERVERNAME,RAT(".",_VFP.SERVERNAME)-1)+".DLL").AND.AT(UPPE(LEFT(_VFP.SERVERNAME,RAT(".",_VFP.SERVERNAME)-1)+".DLL"),UPPE(SET("LIBRARY")))=0
SET LIBRARY TO (LEFT(_VFP.SERVERNAME,RAT(".",_VFP.SERVERNAME)-1)+".DLL") ADDITIVE
ENDI
__VC_JOS_A(39)
READ EVENTS
PROCEDURE __VC_AQBWQP_
__VC_JOS_A(40)
RETURN __VC_JOS_A(41)
PROCEDURE __VC_AQBWQP_1
__VC_JOS_A(42)
RETURN __VC_JOS_A(43)
PROCEDURE __VC_AQBWQP_PRIVATE_1
__VC_JOS_A(44)
RETURN __VC_JOS_A(45)
PROCEDURE __VC_AQBWRC_
PARAMETER m.__VC_AQBWRC_A
__VC_JOS_A(46)
RETURN __VC_JOS_A(47)
PROCEDURE __VC_AQBWRL_
PARAMETER __VC_AQBWRL_A,m.__VC_AQBWRL_B,__VC_AQBWRL_C,m.__VC_AQBWRL_D,m.__VC_AQBWRL_E
*[FOXRUN OFF]
PRIVATE m.__VC_AQBWRL_F
m.__VC_AQBWRL_F=0
FOR EACH __VC_AQBWRL_A &__VC_AQBWRL_B IN &__VC_AQBWRL_C &__VC_AQBWRL_D
m.__VC_AQBWRL_F=m.__VC_AQBWRL_F+1
IF m.__VC_AQBWRL_F>=m.__VC_AQBWRL_E
RETU .T.
ENDI
LOOP
ENDFOR
RETU .F.
*[FOXRUN ON]