On May 13, 12:12 am, Maxwell_House <[email protected]> wrote:
> Hello.
>
> I need to verify signature of the certificate I get from Video Mixing
> Renderer (Microsoft Direct Show) through IAMCertifiedOutputProtection
> interface.http://msdn.microsoft.com/en-us/library/aa468617.aspx#validating_the_...
> I call IAMCertifiedOutputProtection::KeyExchange function and get a key and
> a certificate.
>
> Every step succedes til I get to RSASSA-PSS verification. I use Crypto++ as
> following:http://www.copypastecode.com/70961/?view=lines
>
> And it returns false in cryptopp function 
> RecoverMessageFromRepresentative:http://www.copypastecode.com/70957/?view=lines
> Line 29: salt points to padding zero. As the result, byte *M is 19 zero
> bytes before the wanted 0x01 value.
>
> Does someone have an experience in such questions or has any thoughts on
> what may be wrong? Is it a signature or a message, because I cropped the
> message, but still fail on that line.
>
Just a stab in the dark, but I seem to recall that Microsoft likes to
encode its byte arrays using little endian format (for example,
PUBLICKEYBLOB and PRIVATEKEYBLOB). You might try nudging things a bit
with std::reverse (?) before sending into Crypto++.

Jeff

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