// This code uses the #import directive.
// Put the following line at the beginning of your module 

#import "XCEEDCRY.DLL" no_namespace named_guids 

CoInitialize( NULL ); 

try
{
  IXceedSigningPtr piSign; 

  piSign.CreateInstance( CLSID_XceedSigning ); 
  piSign->License( _bstr_t( L"your license key ) ); 

  IXceedRSASigningMethodPtr piRSA; 
  piRSA.CreateInstance( CLSID_XceedRSASigningMethod );  

  // The following call to SetRandomKeyPair would, in the real world,  
  // be replaced by the assignment of a Private Key to the  
  // PrivateKey property.  

  piRSA->SetRandomKeyPair( 512, NULL, 0 ); 

  piSign->SigningMethod = IXceedSignDataPtr( piRSA );  

  BYTE* pcSignature = NULL; 
  short nSignatureSize; 
  DWORD dwBytesRead;  

  piSign->ReadFile( "c:\\temp\\source.txt", 0, 0, efpSign, TRUE, &dwBytesRead );  

  piRSA->GetSignature( &pcSignature, &nSignatureSize );  

  //Do something with the Signature... 

  CoTaskMemFree( pcSignature );  

  MessageBox( NULL, "File signed successfully to memory", "Signing result", MB_OK );  

  piSign->ReadFile( "c:\\temp\\source.txt", 0, 0, efpVerify, TRUE, &dwBytesRead ); 

  MessageBox( NULL, "Data verified successfully", "Verifying result", MB_OK ); 
}
catch( const _com_error& xErr )
{
  if( xErr.Error() == eerVerifyFailed ) 
  { 
    MessageBox( NULL, "Signature verification failed" , "Verifying result", MB_OK ); 
  } 
  else 
  { 
    char szMsg[50]; 
    wsprintf( szMsg, "Error %08x\n", xErr.Error() ); 
    MessageBox( NULL, szMsg, "Error", MB_OK ); 
  } 
}
catch( ... )
{
  MessageBox( NULL, "Unknown error", "Error", MB_OK ); 
} 

CoUninitialize();