RE: Question about OffloadModExpo() Function

From: lelteto (lelteto_at_discussions.microsoft.com)
Date: 10/23/05 

Date: Sun, 23 Oct 2005 11:14:05 -0700

If your code is called than you can debug it (or print trace values) so you
can check
- what input parameters you get from CAPI
- what result you return
- what result CAPI returns to the calling program
One possible thing: Do you use LITTLE ENDIAN data? If your test program and
OffloadModExpo assumes big endian (ie. network byte order - which is used by
everybody but Microsoft) than you will have problem.

Laszlo Elteto

"JohnShen" wrote:

> Hi Laszlo,
>
> Thank you very much for your answer.
>
> I think my OffLoadModExpo is called by CSP. Because I add some print
> information in OffLoadModExpo. When running the test programs which call
> CAPI, they could print the information.
>
> So are there any other possible reasons? Any information for me will be
> grateful.
>
> --
> John
>
>
> "lelteto" wrote:
>
> > In debugger do you see at all your function called from CAPI? If not, than
> > maybe dll signing is the issue. Capi won't load unsigned CSPs so it's
> > possible that it won't load unsigned OffLoadModExpo dlls either. For testing
> > try to load a KERNEL debugger (because than CAPI allow to load any unsigned
> > dlls). If that solves your problem than it's the dll signature...
> >
> > Laszlo Elteto
> > SafeNet, Inc.
> >
> > "JohnShen" wrote:
> >
> > > Hi everyone,
> > >
> > > MSDN tells that OffloadModExpo() function can offload modular exponentiation
> > > from a CSP to a hardware accelerator.
> > > But these days I've been nearly crazy about this function.
> > >
> > > I implement my own OffloadModExpo() function, which calling the ModExpo
> > > implementation of RSAREF library. And building to a windows DLL.
> > >
> > > Directly calling my OffloadModExpo(), encrypting & decrypting runs OK.
> > > But When use Crypto API, which will indirectly call OffloadModExpo(),
> > > encrypting & decrypting fails.
>