WinVerifyTrust on legacy Win9x?

[Jason De Arte]

I'm interested in finding a method to verify the digital signature of a file so that I'll know if it's been altered since I signed it. I looked at WinVerifyTrust(), but it only exists in NT/XP - not Win9x (which I still need to support). Microsoft does however have a tool called ChkTrust.exe Does anyone know "how" chktrust.exe works under win9x? [ Jason De Arte | Toy Maker | 1001010.com ]

[Jason De Arte]

Well, after a few hours of digging and testing my theories - I've answered my own question. There's this thing called CAPICOM.DLL that provides a number of com interfaces for checking the authenticode signature on a file. And it even (as the rumor goes) have a redistributable for win98! With a little work, I'm sure somebody with more time on their hands than I, could write up a full featured article that also Signs and timestamps a file. :)

#ifndef __SIGNED_CODE_H__
#define __SIGNED_CODE_H__
	
// 2004.Oct.03.JED - A quick tool to check the signatures of an Authenticode signed file
//  coded under DevStudio6 for an ATL/WTL project
	
// MSDN Docs
// http://msdn.microsoft.com/library/default.asp?url=/library/en-us/seccrypto/security/signedcode.asp
	
// Get the typelib header info
#import "capicom.dll" named_guids no_implementation
	
#pragma once
	
class CSignedCode
{
protected:
	CComQIPtr<CAPICOM::ISignedCode> m_spSignedCode;

public:
	CSignedCode(LPCTSTR pszFileName)
	{
		HRESULT hr = m_spSignedCode.CoCreateInstance(CAPICOM::CLSID_SignedCode);
		if( SUCCEEDED(hr) && pszFileName && *pszFileName )
			SetFileName( pszFileName );
	}
	
	// The act of setting the filename starts the Authenticode check
	HRESULT SetFileName( LPCTSTR pszFileName )
	{
		if( !m_spSignedCode )
			return E_POINTER;
		return m_spSignedCode->put_FileName( CComBSTR(pszFileName) );
	}

	// XP SP2, calling with TRUE displays the warning dialog that is displayed
	// when you run an EXE you just downloaded.
	// THIS DOES NOT DO THE ACTUAL CHECK - SetFileName does
	HRESULT Verify(BOOL bAllowWindowsPromptUI)
	{
		if( !m_spSignedCode )
			return E_POINTER;
		return m_spSignedCode->raw_Verify(bAllowWindowsPromptUI?VARIANT_TRUE:VARIANT_FALSE);
	}

	HRESULT GetDescription(CString& rstrDescription)
	{
		if( !m_spSignedCode )
			return E_POINTER;
		CComBSTR bs;
		HRESULT hr = m_spSignedCode->get_Description(&bs);
		if( SUCCEEDED(hr) )
			rstrDescription = bs;
		return hr;
	}

	HRESULT GetURL(CString& rstrDescriptionURL)
	{
		if( !m_spSignedCode )
			return E_POINTER;
		CComBSTR bs;
		HRESULT hr = m_spSignedCode->get_DescriptionURL(&bs);
		if( SUCCEEDED(hr) )
			rstrDescriptionURL = bs;
		return hr;
	}

	HRESULT GetFileName(CString& rstrFileName)
	{
		if( !m_spSignedCode )
			return E_POINTER;
		CComBSTR bs;
		HRESULT hr = m_spSignedCode->get_FileName(&bs);
		if( SUCCEEDED(hr) )
			rstrFileName = bs;
		return hr;
	}
};

#endif //__SIGNED_CODE_H__