// CryptUnprotectData.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <locale.h>

#pragma comment (lib, "Crypt32")

int _tmain(int argc, _TCHAR* argv[])
{
	_tprintf(TEXT(	"======================================================\n= CryptProtectData wrapper by Passcape Software      =\n= Visit http://www.passcape.com for more information =\n======================================================\n\n"));
	if ( argc<2 || argc>4 )
	{
		_tprintf(TEXT("Syntax: %s input_filename [entropy_string] [flags]\n"),argv[0]);
		return 1;
	}

	//Declare variables
	DATA_BLOB DataIn;
	DATA_BLOB DataOut;
	DATA_BLOB DataEntropy;
	DWORD dwFlags;
	LPTSTR pFoo;
	LPTSTR pszDescription=NULL;

	//Initialize the structure
	//read the input blob
	FILE *f=NULL;
	_tfopen_s(&f,argv[1],TEXT("rb"));
	if ( !f )
	{
		_tprintf(TEXT("Can't open input file for reading\n"));
		return 1;
	}

	//allocate memory
	if ( fseek(f,0,SEEK_END) )
	{
errseek:
		_tprintf(TEXT("Can't determine input file size\n"));
		fclose(f);
		return 2;
	}
	DataIn.cbData=(DWORD)ftell(f);
	if ( fseek(f,0,SEEK_SET) )
		goto errseek;

	DataIn.pbData=new BYTE [DataIn.cbData];
	if ( !DataIn.pbData )
	{
		_tprintf(TEXT("Can't allocate %lu memory bytes\n"),DataIn.cbData);
		fclose(f);
		return 3;
	}

	//read DPAPI blob
	if ( fread(DataIn.pbData,DataIn.cbData,1,f)!=1 )
	{
		delete(DataIn.pbData);
		DataIn.pbData=NULL;
		_tprintf(TEXT("Can't read data blob\n"));
		fclose(f);
		return 4;
	}
	fclose(f);

	//
	DataOut.pbData=NULL;
	DataOut.cbData=0;
	//
	if ( argc>=3 )
	{
		DataEntropy.pbData=(LPBYTE)(argv[2]);
		DataEntropy.cbData=(lstrlen(argv[2])+1) * sizeof(TCHAR) ;
	}
	//
	if ( argc==4 )
		dwFlags=_tcstoul(argv[3],&pFoo,10);
	else
		dwFlags=0;

	//Unprotect it
	int iRet=0;
	if ( !CryptUnprotectData(
		&DataIn,
		&pszDescription,				//description string to be included
		argc>=3?&DataEntropy:NULL,		//Optional entropy
		NULL,							//reserved
		NULL,							//prompt structure, not used
		dwFlags,						//flags
		&DataOut) )
	{
		dwFlags=GetLastError();
		_tprintf(TEXT("CryptUnprotectData failed with the following error code: %lu\n"),dwFlags);
		iRet=5;
		goto ex;
	}

	//turn on internationalization
	_tsetlocale(LC_ALL,TEXT(""));
	//out put decrypted data
	_tprintf(TEXT("Data blob description: %s\n"),pszDescription?pszDescription:TEXT(""));
	_tprintf(TEXT("Data size: %lu\n"),DataOut.cbData);
	_tprintf(TEXT("Decrypted data: "));
	if ( pszDescription && lstrcmp(pszDescription,TEXT("CryptProtectData by Passcape Software"))==0 )
		_tprintf(TEXT("%s"),DataOut.pbData?(LPTSTR)DataOut.pbData:TEXT(""));
	else
	{
		for ( DWORD dw=0; dw<DataOut.cbData; dw++ )
			_tprintf(TEXT("%02X "),((LPBYTE)pszDescription)[dw]);
	}
	_tprintf(TEXT("\n"));
	
ex:
	//free resources
	if ( pszDescription )
	{
		LocalFree(pszDescription);
		pszDescription=NULL;
	}

	if ( DataOut.pbData )
	{
		LocalFree(DataOut.pbData);
		DataOut.pbData=NULL;
	}

	return iRet;
}