crypto/rand/rand_win.c - third_party/openssl - Git at Google

 /* crypto/rand/rand_win.c */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
  * This package is an SSL implementation written
  * by Eric Young (eay@cryptsoft.com).
  * The implementation was written so as to conform with Netscapes SSL.
  *
  * This library is free for commercial and non-commercial use as long as
  * the following conditions are aheared to.  The following conditions
  * apply to all code found in this distribution, be it the RC4, RSA,
  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  * included with this distribution is covered by the same copyright terms
  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  *
  * Copyright remains Eric Young's, and as such any Copyright notices in
  * the code are not to be removed.
  * If this package is used in a product, Eric Young should be given attribution
  * as the author of the parts of the library used.
  * This can be in the form of a textual message at program startup or
  * in documentation (online or textual) provided with the package.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  * 3. All advertising materials mentioning features or use of this software
  *    must display the following acknowledgement:
  *    "This product includes cryptographic software written by
  *     Eric Young (eay@cryptsoft.com)"
  *    The word 'cryptographic' can be left out if the rouines from the library
  *    being used are not cryptographic related :-).
  * 4. If you include any Windows specific code (or a derivative thereof) from
  *    the apps directory (application code) you must include an acknowledgement:
  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  *
  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
  * The licence and distribution terms for any publically available version or
  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  * copied and put under another distribution licence
  * [including the GNU Public Licence.]
  */
 /* ====================================================================
  * Copyright (c) 1998-2000 The OpenSSL Project.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  *
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *    the documentation and/or other materials provided with the
  *    distribution.
  *
  * 3. All advertising materials mentioning features or use of this
  *    software must display the following acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  *
  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  *    endorse or promote products derived from this software without
  *    prior written permission. For written permission, please contact
  *    openssl-core@openssl.org.
  *
  * 5. Products derived from this software may not be called "OpenSSL"
  *    nor may "OpenSSL" appear in their names without prior written
  *    permission of the OpenSSL Project.
  *
  * 6. Redistributions of any form whatsoever must retain the following
  *    acknowledgment:
  *    "This product includes software developed by the OpenSSL Project
  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  *
  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  * OF THE POSSIBILITY OF SUCH DAMAGE.
  * ====================================================================
  *
  * This product includes cryptographic software written by Eric Young
  * (eay@cryptsoft.com).  This product includes software written by Tim
  * Hudson (tjh@cryptsoft.com).
  *
  */

 #include "cryptlib.h"
 #include <openssl/rand.h>
 #include "rand_lcl.h"

 #if defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32)
 #include <windows.h>
 #ifndef _WIN32_WINNT
 # define _WIN32_WINNT 0x0400
 #endif
 #include <wincrypt.h>
 #include <tlhelp32.h>

 /* Intel hardware RNG CSP -- available from
  * http://developer.intel.com/design/security/rng/redist_license.htm
  */
 #define PROV_INTEL_SEC 22
 #define INTEL_DEF_PROV "Intel Hardware Cryptographic Service Provider"

 static void readtimer(void);
 static void readscreen(void);

 /* It appears like CURSORINFO, PCURSORINFO and LPCURSORINFO are only defined
    when WINVER is 0x0500 and up, which currently only happens on Win2000.
    Unfortunately, those are typedefs, so they're a little bit difficult to
    detect properly.  On the other hand, the macro CURSOR_SHOWING is defined
    within the same conditional, so it can be use to detect the absence of said
    typedefs. */

 #ifndef CURSOR_SHOWING
 /*
  * Information about the global cursor.
  */
 typedef struct tagCURSORINFO
 {
     DWORD   cbSize;
     DWORD   flags;
     HCURSOR hCursor;
     POINT   ptScreenPos;
 } CURSORINFO, *PCURSORINFO, *LPCURSORINFO;

 #define CURSOR_SHOWING     0x00000001
 #endif /* CURSOR_SHOWING */

 typedef BOOL (WINAPI *CRYPTACQUIRECONTEXT)(HCRYPTPROV *, LPCTSTR, LPCTSTR,
 				    DWORD, DWORD);
 typedef BOOL (WINAPI *CRYPTGENRANDOM)(HCRYPTPROV, DWORD, BYTE *);
 typedef BOOL (WINAPI *CRYPTRELEASECONTEXT)(HCRYPTPROV, DWORD);

 typedef HWND (WINAPI *GETFOREGROUNDWINDOW)(VOID);
 typedef BOOL (WINAPI *GETCURSORINFO)(PCURSORINFO);
 typedef DWORD (WINAPI *GETQUEUESTATUS)(UINT);

 typedef HANDLE (WINAPI *CREATETOOLHELP32SNAPSHOT)(DWORD, DWORD);
 typedef BOOL (WINAPI *HEAP32FIRST)(LPHEAPENTRY32, DWORD, DWORD);
 typedef BOOL (WINAPI *HEAP32NEXT)(LPHEAPENTRY32);
 typedef BOOL (WINAPI *HEAP32LIST)(HANDLE, LPHEAPLIST32);
 typedef BOOL (WINAPI *PROCESS32)(HANDLE, LPPROCESSENTRY32);
 typedef BOOL (WINAPI *THREAD32)(HANDLE, LPTHREADENTRY32);
 typedef BOOL (WINAPI *MODULE32)(HANDLE, LPMODULEENTRY32);

 #include <lmcons.h>
 #include <lmstats.h>
 #if 1 /* The NET API is Unicode only.  It requires the use of the UNICODE
        * macro.  When UNICODE is defined LPTSTR becomes LPWSTR.  LMSTR was
        * was added to the Platform SDK to allow the NET API to be used in
        * non-Unicode applications provided that Unicode strings were still
        * used for input.  LMSTR is defined as LPWSTR.
        */
 typedef NET_API_STATUS (NET_API_FUNCTION * NETSTATGET)
         (LPWSTR, LPWSTR, DWORD, DWORD, LPBYTE*);
 typedef NET_API_STATUS (NET_API_FUNCTION * NETFREE)(LPBYTE);
 #endif /* 1 */

 int RAND_poll(void)
 {
 	MEMORYSTATUS m;
 	HCRYPTPROV hProvider = 0;
 	BYTE buf[64];
 	DWORD w;
 	HWND h;

 	HMODULE advapi, kernel, user, netapi;
 	CRYPTACQUIRECONTEXT acquire = 0;
 	CRYPTGENRANDOM gen = 0;
 	CRYPTRELEASECONTEXT release = 0;
 #if 1 /* There was previously a problem with NETSTATGET.  Currently, this
        * section is still experimental, but if all goes well, this conditional
        * will be removed
        */
 	NETSTATGET netstatget = 0;
 	NETFREE netfree = 0;
 #endif /* 1 */

 	/* Determine the OS version we are on so we can turn off things
 	 * that do not work properly.
 	 */
         OSVERSIONINFO osverinfo ;
         osverinfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO) ;
         GetVersionEx( &osverinfo ) ;

 	/* load functions dynamically - not available on all systems */
 	advapi = LoadLibrary("ADVAPI32.DLL");
 	kernel = LoadLibrary("KERNEL32.DLL");
 	user = LoadLibrary("USER32.DLL");
 	netapi = LoadLibrary("NETAPI32.DLL");

 #if 1 /* There was previously a problem with NETSTATGET.  Currently, this
        * section is still experimental, but if all goes well, this conditional
        * will be removed
        */
 	if (netapi)
 		{
 		netstatget = (NETSTATGET) GetProcAddress(netapi,"NetStatisticsGet");
 		netfree = (NETFREE) GetProcAddress(netapi,"NetApiBufferFree");
 		}

 	if (netstatget && netfree)
 		{
 		LPBYTE outbuf;
 		/* NetStatisticsGet() is a Unicode only function
  		 * STAT_WORKSTATION_0 contains 45 fields and STAT_SERVER_0
 		 * contains 17 fields.  We treat each field as a source of
 		 * one byte of entropy.
                  */

 		if (netstatget(NULL, L"LanmanWorkstation", 0, 0, &outbuf) == 0)
 			{
 			RAND_add(outbuf, sizeof(STAT_WORKSTATION_0), 45);
 			netfree(outbuf);
 			}
 		if (netstatget(NULL, L"LanmanServer", 0, 0, &outbuf) == 0)
 			{
 			RAND_add(outbuf, sizeof(STAT_SERVER_0), 17);
 			netfree(outbuf);
 			}
 		}

 	if (netapi)
 		FreeLibrary(netapi);
 #endif /* 1 */

         /* It appears like this can cause an exception deep within ADVAPI32.DLL
          * at random times on Windows 2000.  Reported by Jeffrey Altman.
          * Only use it on NT.
 	 */
 	/* Wolfgang Marczy <WMarczy@topcall.co.at> reports that
 	 * the RegQueryValueEx call below can hang on NT4.0 (SP6).
 	 * So we don't use this at all for now. */
 #if 0
         if ( osverinfo.dwPlatformId == VER_PLATFORM_WIN32_NT &&
 		osverinfo.dwMajorVersion < 5)
 		{
 		/* Read Performance Statistics from NT/2000 registry
 		 * The size of the performance data can vary from call
 		 * to call so we must guess the size of the buffer to use
 		 * and increase its size if we get an ERROR_MORE_DATA
 		 * return instead of ERROR_SUCCESS.
 		 */
 		LONG   rc=ERROR_MORE_DATA;
 		char * buf=NULL;
 		DWORD bufsz=0;
 		DWORD length;

 		while (rc == ERROR_MORE_DATA)
 			{
 			buf = realloc(buf,bufsz+8192);
 			if (!buf)
 				break;
 			bufsz += 8192;

 			length = bufsz;
 			rc = RegQueryValueEx(HKEY_PERFORMANCE_DATA, "Global",
 				NULL, NULL, buf, &length);
 			}
 		if (rc == ERROR_SUCCESS)
 			{
                         /* For entropy count assume only least significant
 			 * byte of each DWORD is random.
                          */
 			RAND_add(&length, sizeof(length), 0);
 			RAND_add(buf, length, length / 4.0);
 			}
 		if (buf)
 			free(buf);
 		}
 #endif

 	if (advapi)
 		{
 		acquire = (CRYPTACQUIRECONTEXT) GetProcAddress(advapi,
 			"CryptAcquireContextA");
 		gen = (CRYPTGENRANDOM) GetProcAddress(advapi,
 			"CryptGenRandom");
 		release = (CRYPTRELEASECONTEXT) GetProcAddress(advapi,
 			"CryptReleaseContext");
 		}

 	if (acquire && gen && release)
 		{
 		/* poll the CryptoAPI PRNG */
                 /* The CryptoAPI returns sizeof(buf) bytes of randomness */
 		if (acquire(&hProvider, 0, 0, PROV_RSA_FULL,
 			CRYPT_VERIFYCONTEXT))
 			{
 			if (gen(hProvider, sizeof(buf), buf) != 0)
 				{
 				RAND_add(buf, sizeof(buf), 0);
 #ifdef DEBUG
 				printf("randomness from PROV_RSA_FULL\n");
 #endif
 				}
 			release(hProvider, 0);
 			}

 		/* poll the Pentium PRG with CryptoAPI */
 		if (acquire(&hProvider, 0, INTEL_DEF_PROV, PROV_INTEL_SEC, 0))
 			{
 			if (gen(hProvider, sizeof(buf), buf) != 0)
 				{
 				RAND_add(buf, sizeof(buf), sizeof(buf));
 #ifdef DEBUG
 				printf("randomness from PROV_INTEL_SEC\n");
 #endif
 				}
 			release(hProvider, 0);
 			}
 		}

         if (advapi)
 		FreeLibrary(advapi);

 	/* timer data */
 	readtimer();

 	/* memory usage statistics */
 	GlobalMemoryStatus(&m);
 	RAND_add(&m, sizeof(m), 1);

 	/* process ID */
 	w = GetCurrentProcessId();
 	RAND_add(&w, sizeof(w), 1);

 	if (user)
 		{
 		GETCURSORINFO cursor;
 		GETFOREGROUNDWINDOW win;
 		GETQUEUESTATUS queue;

 		win = (GETFOREGROUNDWINDOW) GetProcAddress(user, "GetForegroundWindow");
 		cursor = (GETCURSORINFO) GetProcAddress(user, "GetCursorInfo");
 		queue = (GETQUEUESTATUS) GetProcAddress(user, "GetQueueStatus");

 		if (win)
 			{
 			/* window handle */
 			h = win();
 			RAND_add(&h, sizeof(h), 0);
 			}
 		if (cursor)
 			{
 			/* unfortunately, its not safe to call GetCursorInfo()
 			 * on NT4 even though it exists in SP3 (or SP6) and
 			 * higher.
 			 */
 			if ( osverinfo.dwPlatformId == VER_PLATFORM_WIN32_NT &&
 				osverinfo.dwMajorVersion < 5)
 				cursor = 0;
 			}
 		if (cursor)
 			{
 			/* cursor position */
                         /* assume 2 bytes of entropy */
 			CURSORINFO ci;
 			ci.cbSize = sizeof(CURSORINFO);
 			if (cursor(&ci))
 				RAND_add(&ci, ci.cbSize, 2);
 			}

 		if (queue)
 			{
 			/* message queue status */
                         /* assume 1 byte of entropy */
 			w = queue(QS_ALLEVENTS);
 			RAND_add(&w, sizeof(w), 1);
 			}

 		FreeLibrary(user);
 		}

 	/* Toolhelp32 snapshot: enumerate processes, threads, modules and heap
 	 * http://msdn.microsoft.com/library/psdk/winbase/toolhelp_5pfd.htm
 	 * (Win 9x and 2000 only, not available on NT)
 	 *
 	 * This seeding method was proposed in Peter Gutmann, Software
 	 * Generation of Practically Strong Random Numbers,
 	 * http://www.usenix.org/publications/library/proceedings/sec98/gutmann.html
      * revised version at http://www.cryptoengines.com/~peter/06_random.pdf
 	 * (The assignment of entropy estimates below is arbitrary, but based
 	 * on Peter's analysis the full poll appears to be safe. Additional
 	 * interactive seeding is encouraged.)
 	 */

 	if (kernel)
 		{
 		CREATETOOLHELP32SNAPSHOT snap;
 		HANDLE handle;

 		HEAP32FIRST heap_first;
 		HEAP32NEXT heap_next;
 		HEAP32LIST heaplist_first, heaplist_next;
 		PROCESS32 process_first, process_next;
 		THREAD32 thread_first, thread_next;
 		MODULE32 module_first, module_next;

 		HEAPLIST32 hlist;
 		HEAPENTRY32 hentry;
 		PROCESSENTRY32 p;
 		THREADENTRY32 t;
 		MODULEENTRY32 m;

 		snap = (CREATETOOLHELP32SNAPSHOT)
 			GetProcAddress(kernel, "CreateToolhelp32Snapshot");
 		heap_first = (HEAP32FIRST) GetProcAddress(kernel, "Heap32First");
 		heap_next = (HEAP32NEXT) GetProcAddress(kernel, "Heap32Next");
 		heaplist_first = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListFirst");
 		heaplist_next = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListNext");
 		process_first = (PROCESS32) GetProcAddress(kernel, "Process32First");
 		process_next = (PROCESS32) GetProcAddress(kernel, "Process32Next");
 		thread_first = (THREAD32) GetProcAddress(kernel, "Thread32First");
 		thread_next = (THREAD32) GetProcAddress(kernel, "Thread32Next");
 		module_first = (MODULE32) GetProcAddress(kernel, "Module32First");
 		module_next = (MODULE32) GetProcAddress(kernel, "Module32Next");

 		if (snap && heap_first && heap_next && heaplist_first &&
 			heaplist_next && process_first && process_next &&
 			thread_first && thread_next && module_first &&
 			module_next && (handle = snap(TH32CS_SNAPALL,0))
 			!= NULL)
 			{
 			/* heap list and heap walking */
                         /* HEAPLIST32 contains 3 fields that will change with
                          * each entry.  Consider each field a source of 1 byte
                          * of entropy.
                          * HEAPENTRY32 contains 5 fields that will change with
                          * each entry.  Consider each field a source of 1 byte
                          * of entropy.
                          */
 			hlist.dwSize = sizeof(HEAPLIST32);
 			if (heaplist_first(handle, &hlist))
 				do
 					{
 					RAND_add(&hlist, hlist.dwSize, 3);
 					hentry.dwSize = sizeof(HEAPENTRY32);
 					if (heap_first(&hentry,
 						hlist.th32ProcessID,
 						hlist.th32HeapID))
 						{
 						int entrycnt = 80;
 						do
 							RAND_add(&hentry,
 								hentry.dwSize, 5);
 						while (heap_next(&hentry)
 							&& --entrycnt > 0);
 						}
 					} while (heaplist_next(handle,
 						&hlist));

 			/* process walking */
                         /* PROCESSENTRY32 contains 9 fields that will change
                          * with each entry.  Consider each field a source of
                          * 1 byte of entropy.
                          */
 			p.dwSize = sizeof(PROCESSENTRY32);
 			if (process_first(handle, &p))
 				do
 					RAND_add(&p, p.dwSize, 9);
 				while (process_next(handle, &p));

 			/* thread walking */
                         /* THREADENTRY32 contains 6 fields that will change
                          * with each entry.  Consider each field a source of
                          * 1 byte of entropy.
                          */
 			t.dwSize = sizeof(THREADENTRY32);
 			if (thread_first(handle, &t))
 				do
 					RAND_add(&t, t.dwSize, 6);
 				while (thread_next(handle, &t));

 			/* module walking */
                         /* MODULEENTRY32 contains 9 fields that will change
                          * with each entry.  Consider each field a source of
                          * 1 byte of entropy.
                          */
 			m.dwSize = sizeof(MODULEENTRY32);
 			if (module_first(handle, &m))
 				do
 					RAND_add(&m, m.dwSize, 9);
 				while (module_next(handle, &m));

 			CloseHandle(handle);
 			}

 		FreeLibrary(kernel);
 		}

 #ifdef DEBUG
 	printf("Exiting RAND_poll\n");
 #endif

 	return(1);
 }

 int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam)
         {
         double add_entropy=0;

         switch (iMsg)
                 {
         case WM_KEYDOWN:
                         {
                         static WPARAM key;
                         if (key != wParam)
                                 add_entropy = 0.05;
                         key = wParam;
                         }
                         break;
 	case WM_MOUSEMOVE:
                         {
                         static int lastx,lasty,lastdx,lastdy;
                         int x,y,dx,dy;

                         x=LOWORD(lParam);
                         y=HIWORD(lParam);
                         dx=lastx-x;
                         dy=lasty-y;
                         if (dx != 0 && dy != 0 && dx-lastdx != 0 && dy-lastdy != 0)
                                 add_entropy=.2;
                         lastx=x, lasty=y;
                         lastdx=dx, lastdy=dy;
                         }
 		break;
 		}

 	readtimer();
         RAND_add(&iMsg, sizeof(iMsg), add_entropy);
 	RAND_add(&wParam, sizeof(wParam), 0);
 	RAND_add(&lParam, sizeof(lParam), 0);

 	return (RAND_status());
 	}


 void RAND_screen(void) /* function available for backward compatibility */
 {
 	RAND_poll();
 	readscreen();
 }


 /* feed timing information to the PRNG */
 static void readtimer(void)
 {
 	DWORD w;
 	LARGE_INTEGER l;
 	static int have_perfc = 1;
 #ifdef _MSC_VER
 	static int have_tsc = 1;
 	DWORD cyclecount;

 	if (have_tsc) {
 	  __try {
 	    __asm {
 	      rdtsc
 	      mov cyclecount, eax
 	      }
 	    RAND_add(&cyclecount, sizeof(cyclecount), 1);
 	  } __except(EXCEPTION_EXECUTE_HANDLER) {
 	    have_tsc = 0;
 	  }
 	}
 #else
 # define have_tsc 0
 #endif

 	if (have_perfc) {
 	  if (QueryPerformanceCounter(&l) == 0)
 	    have_perfc = 0;
 	  else
 	    RAND_add(&l, sizeof(l), 0);
 	}

 	if (!have_tsc && !have_perfc) {
 	  w = GetTickCount();
 	  RAND_add(&w, sizeof(w), 0);
 	}
 }

 /* feed screen contents to PRNG */
 /*****************************************************************************
  *
  * Created 960901 by Gertjan van Oosten, gertjan@West.NL, West Consulting B.V.
  *
  * Code adapted from
  * <URL:http://www.microsoft.com/kb/developr/win_dk/q97193.htm>;
  * the original copyright message is:
  *
  *   (C) Copyright Microsoft Corp. 1993.  All rights reserved.
  *
  *   You have a royalty-free right to use, modify, reproduce and
  *   distribute the Sample Files (and/or any modified version) in
  *   any way you find useful, provided that you agree that
  *   Microsoft has no warranty obligations or liability for any
  *   Sample Application Files which are modified.
  */

 static void readscreen(void)
 {
   HDC		hScrDC;		/* screen DC */
   HDC		hMemDC;		/* memory DC */
   HBITMAP	hBitmap;	/* handle for our bitmap */
   HBITMAP	hOldBitmap;	/* handle for previous bitmap */
   BITMAP	bm;		/* bitmap properties */
   unsigned int	size;		/* size of bitmap */
   char		*bmbits;	/* contents of bitmap */
   int		w;		/* screen width */
   int		h;		/* screen height */
   int		y;		/* y-coordinate of screen lines to grab */
   int		n = 16;		/* number of screen lines to grab at a time */

   /* Create a screen DC and a memory DC compatible to screen DC */
   hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
   hMemDC = CreateCompatibleDC(hScrDC);

   /* Get screen resolution */
   w = GetDeviceCaps(hScrDC, HORZRES);
   h = GetDeviceCaps(hScrDC, VERTRES);

   /* Create a bitmap compatible with the screen DC */
   hBitmap = CreateCompatibleBitmap(hScrDC, w, n);

   /* Select new bitmap into memory DC */
   hOldBitmap = SelectObject(hMemDC, hBitmap);

   /* Get bitmap properties */
   GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&bm);
   size = (unsigned int)bm.bmWidthBytes * bm.bmHeight * bm.bmPlanes;

   bmbits = OPENSSL_malloc(size);
   if (bmbits) {
     /* Now go through the whole screen, repeatedly grabbing n lines */
     for (y = 0; y < h-n; y += n)
     	{
 	unsigned char md[MD_DIGEST_LENGTH];

 	/* Bitblt screen DC to memory DC */
 	BitBlt(hMemDC, 0, 0, w, n, hScrDC, 0, y, SRCCOPY);

 	/* Copy bitmap bits from memory DC to bmbits */
 	GetBitmapBits(hBitmap, size, bmbits);

 	/* Get the hash of the bitmap */
 	MD(bmbits,size,md);

 	/* Seed the random generator with the hash value */
 	RAND_add(md, MD_DIGEST_LENGTH, 0);
 	}

     OPENSSL_free(bmbits);
   }

   /* Select old bitmap back into memory DC */
   hBitmap = SelectObject(hMemDC, hOldBitmap);

   /* Clean up */
   DeleteObject(hBitmap);
   DeleteDC(hMemDC);
   DeleteDC(hScrDC);
 }

 #endif
	/* crypto/rand/rand_win.c */
	/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
	* All rights reserved.
	*
	* This package is an SSL implementation written
	* by Eric Young (eay@cryptsoft.com).
	* The implementation was written so as to conform with Netscapes SSL.
	*
	* This library is free for commercial and non-commercial use as long as
	* the following conditions are aheared to. The following conditions
	* apply to all code found in this distribution, be it the RC4, RSA,
	* lhash, DES, etc., code; not just the SSL code. The SSL documentation
	* included with this distribution is covered by the same copyright terms
	* except that the holder is Tim Hudson (tjh@cryptsoft.com).
	*
	* Copyright remains Eric Young's, and as such any Copyright notices in
	* the code are not to be removed.
	* If this package is used in a product, Eric Young should be given attribution
	* as the author of the parts of the library used.
	* This can be in the form of a textual message at program startup or
	* in documentation (online or textual) provided with the package.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 3. All advertising materials mentioning features or use of this software
	* must display the following acknowledgement:
	* "This product includes cryptographic software written by
	* Eric Young (eay@cryptsoft.com)"
	* The word 'cryptographic' can be left out if the rouines from the library
	* being used are not cryptographic related :-).
	* 4. If you include any Windows specific code (or a derivative thereof) from
	* the apps directory (application code) you must include an acknowledgement:
	* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
	*
	* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	* SUCH DAMAGE.
	*
	* The licence and distribution terms for any publically available version or
	* derivative of this code cannot be changed. i.e. this code cannot simply be
	* copied and put under another distribution licence
	* [including the GNU Public Licence.]
	*/
	/* ====================================================================
	* Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in
	* the documentation and/or other materials provided with the
	* distribution.
	*
	* 3. All advertising materials mentioning features or use of this
	* software must display the following acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
	*
	* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
	* endorse or promote products derived from this software without
	* prior written permission. For written permission, please contact
	* openssl-core@openssl.org.
	*
	* 5. Products derived from this software may not be called "OpenSSL"
	* nor may "OpenSSL" appear in their names without prior written
	* permission of the OpenSSL Project.
	*
	* 6. Redistributions of any form whatsoever must retain the following
	* acknowledgment:
	* "This product includes software developed by the OpenSSL Project
	* for use in the OpenSSL Toolkit (http://www.openssl.org/)"
	*
	* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
	* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
	* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
	* OF THE POSSIBILITY OF SUCH DAMAGE.
	* ====================================================================
	*
	* This product includes cryptographic software written by Eric Young
	* (eay@cryptsoft.com). This product includes software written by Tim
	* Hudson (tjh@cryptsoft.com).
	*
	*/

	#include "cryptlib.h"
	#include <openssl/rand.h>
	#include "rand_lcl.h"

	#if defined(OPENSSL_SYS_WINDOWS) \|\| defined(OPENSSL_SYS_WIN32)
	#include <windows.h>
	#ifndef _WIN32_WINNT
	# define _WIN32_WINNT 0x0400
	#endif
	#include <wincrypt.h>
	#include <tlhelp32.h>

	/* Intel hardware RNG CSP -- available from
	* http://developer.intel.com/design/security/rng/redist_license.htm
	*/
	#define PROV_INTEL_SEC 22
	#define INTEL_DEF_PROV "Intel Hardware Cryptographic Service Provider"

	static void readtimer(void);
	static void readscreen(void);

	/* It appears like CURSORINFO, PCURSORINFO and LPCURSORINFO are only defined
	when WINVER is 0x0500 and up, which currently only happens on Win2000.
	Unfortunately, those are typedefs, so they're a little bit difficult to
	detect properly. On the other hand, the macro CURSOR_SHOWING is defined
	within the same conditional, so it can be use to detect the absence of said
	typedefs. */

	#ifndef CURSOR_SHOWING
	/*
	* Information about the global cursor.
	*/
	typedef struct tagCURSORINFO
	{
	DWORD cbSize;
	DWORD flags;
	HCURSOR hCursor;
	POINT ptScreenPos;
	} CURSORINFO, PCURSORINFO, LPCURSORINFO;

	#define CURSOR_SHOWING 0x00000001
	#endif /* CURSOR_SHOWING */

	typedef BOOL (WINAPI CRYPTACQUIRECONTEXT)(HCRYPTPROV , LPCTSTR, LPCTSTR,
	DWORD, DWORD);
	typedef BOOL (WINAPI CRYPTGENRANDOM)(HCRYPTPROV, DWORD, BYTE );
	typedef BOOL (WINAPI *CRYPTRELEASECONTEXT)(HCRYPTPROV, DWORD);

	typedef HWND (WINAPI *GETFOREGROUNDWINDOW)(VOID);
	typedef BOOL (WINAPI *GETCURSORINFO)(PCURSORINFO);
	typedef DWORD (WINAPI *GETQUEUESTATUS)(UINT);

	typedef HANDLE (WINAPI *CREATETOOLHELP32SNAPSHOT)(DWORD, DWORD);
	typedef BOOL (WINAPI *HEAP32FIRST)(LPHEAPENTRY32, DWORD, DWORD);
	typedef BOOL (WINAPI *HEAP32NEXT)(LPHEAPENTRY32);
	typedef BOOL (WINAPI *HEAP32LIST)(HANDLE, LPHEAPLIST32);
	typedef BOOL (WINAPI *PROCESS32)(HANDLE, LPPROCESSENTRY32);
	typedef BOOL (WINAPI *THREAD32)(HANDLE, LPTHREADENTRY32);
	typedef BOOL (WINAPI *MODULE32)(HANDLE, LPMODULEENTRY32);

	#include <lmcons.h>
	#include <lmstats.h>
	#if 1 /* The NET API is Unicode only. It requires the use of the UNICODE
	* macro. When UNICODE is defined LPTSTR becomes LPWSTR. LMSTR was
	* was added to the Platform SDK to allow the NET API to be used in
	* non-Unicode applications provided that Unicode strings were still
	* used for input. LMSTR is defined as LPWSTR.
	*/
	typedef NET_API_STATUS (NET_API_FUNCTION * NETSTATGET)
	(LPWSTR, LPWSTR, DWORD, DWORD, LPBYTE*);
	typedef NET_API_STATUS (NET_API_FUNCTION * NETFREE)(LPBYTE);
	#endif /* 1 */

	int RAND_poll(void)
	{
	MEMORYSTATUS m;
	HCRYPTPROV hProvider = 0;
	BYTE buf[64];
	DWORD w;
	HWND h;

	HMODULE advapi, kernel, user, netapi;
	CRYPTACQUIRECONTEXT acquire = 0;
	CRYPTGENRANDOM gen = 0;
	CRYPTRELEASECONTEXT release = 0;
	#if 1 /* There was previously a problem with NETSTATGET. Currently, this
	* section is still experimental, but if all goes well, this conditional
	* will be removed
	*/
	NETSTATGET netstatget = 0;
	NETFREE netfree = 0;
	#endif /* 1 */

	/* Determine the OS version we are on so we can turn off things
	* that do not work properly.
	*/
	OSVERSIONINFO osverinfo ;
	osverinfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO) ;
	GetVersionEx( &osverinfo ) ;

	/* load functions dynamically - not available on all systems */
	advapi = LoadLibrary("ADVAPI32.DLL");
	kernel = LoadLibrary("KERNEL32.DLL");
	user = LoadLibrary("USER32.DLL");
	netapi = LoadLibrary("NETAPI32.DLL");

	#if 1 /* There was previously a problem with NETSTATGET. Currently, this
	* section is still experimental, but if all goes well, this conditional
	* will be removed
	*/
	if (netapi)
	{
	netstatget = (NETSTATGET) GetProcAddress(netapi,"NetStatisticsGet");
	netfree = (NETFREE) GetProcAddress(netapi,"NetApiBufferFree");
	}

	if (netstatget && netfree)
	{
	LPBYTE outbuf;
	/* NetStatisticsGet() is a Unicode only function
	* STAT_WORKSTATION_0 contains 45 fields and STAT_SERVER_0
	* contains 17 fields. We treat each field as a source of
	* one byte of entropy.
	*/

	if (netstatget(NULL, L"LanmanWorkstation", 0, 0, &outbuf) == 0)
	{
	RAND_add(outbuf, sizeof(STAT_WORKSTATION_0), 45);
	netfree(outbuf);
	}
	if (netstatget(NULL, L"LanmanServer", 0, 0, &outbuf) == 0)
	{
	RAND_add(outbuf, sizeof(STAT_SERVER_0), 17);
	netfree(outbuf);
	}
	}

	if (netapi)
	FreeLibrary(netapi);
	#endif /* 1 */

	/* It appears like this can cause an exception deep within ADVAPI32.DLL
	* at random times on Windows 2000. Reported by Jeffrey Altman.
	* Only use it on NT.
	*/
	/* Wolfgang Marczy <WMarczy@topcall.co.at> reports that
	* the RegQueryValueEx call below can hang on NT4.0 (SP6).
	* So we don't use this at all for now. */
	#if 0
	if ( osverinfo.dwPlatformId == VER_PLATFORM_WIN32_NT &&
	osverinfo.dwMajorVersion < 5)
	{
	/* Read Performance Statistics from NT/2000 registry
	* The size of the performance data can vary from call
	* to call so we must guess the size of the buffer to use
	* and increase its size if we get an ERROR_MORE_DATA
	* return instead of ERROR_SUCCESS.
	*/
	LONG rc=ERROR_MORE_DATA;
	char * buf=NULL;
	DWORD bufsz=0;
	DWORD length;

	while (rc == ERROR_MORE_DATA)
	{
	buf = realloc(buf,bufsz+8192);
	if (!buf)
	break;
	bufsz += 8192;

	length = bufsz;
	rc = RegQueryValueEx(HKEY_PERFORMANCE_DATA, "Global",
	NULL, NULL, buf, &length);
	}
	if (rc == ERROR_SUCCESS)
	{
	/* For entropy count assume only least significant
	* byte of each DWORD is random.
	*/
	RAND_add(&length, sizeof(length), 0);
	RAND_add(buf, length, length / 4.0);
	}
	if (buf)
	free(buf);
	}
	#endif

	if (advapi)
	{
	acquire = (CRYPTACQUIRECONTEXT) GetProcAddress(advapi,
	"CryptAcquireContextA");
	gen = (CRYPTGENRANDOM) GetProcAddress(advapi,
	"CryptGenRandom");
	release = (CRYPTRELEASECONTEXT) GetProcAddress(advapi,
	"CryptReleaseContext");
	}

	if (acquire && gen && release)
	{
	/* poll the CryptoAPI PRNG */
	/* The CryptoAPI returns sizeof(buf) bytes of randomness */
	if (acquire(&hProvider, 0, 0, PROV_RSA_FULL,
	CRYPT_VERIFYCONTEXT))
	{
	if (gen(hProvider, sizeof(buf), buf) != 0)
	{
	RAND_add(buf, sizeof(buf), 0);
	#ifdef DEBUG
	printf("randomness from PROV_RSA_FULL\n");
	#endif
	}
	release(hProvider, 0);
	}

	/* poll the Pentium PRG with CryptoAPI */
	if (acquire(&hProvider, 0, INTEL_DEF_PROV, PROV_INTEL_SEC, 0))
	{
	if (gen(hProvider, sizeof(buf), buf) != 0)
	{
	RAND_add(buf, sizeof(buf), sizeof(buf));
	#ifdef DEBUG
	printf("randomness from PROV_INTEL_SEC\n");
	#endif
	}
	release(hProvider, 0);
	}
	}

	if (advapi)
	FreeLibrary(advapi);

	/* timer data */
	readtimer();

	/* memory usage statistics */
	GlobalMemoryStatus(&m);
	RAND_add(&m, sizeof(m), 1);

	/* process ID */
	w = GetCurrentProcessId();
	RAND_add(&w, sizeof(w), 1);

	if (user)
	{
	GETCURSORINFO cursor;
	GETFOREGROUNDWINDOW win;
	GETQUEUESTATUS queue;

	win = (GETFOREGROUNDWINDOW) GetProcAddress(user, "GetForegroundWindow");
	cursor = (GETCURSORINFO) GetProcAddress(user, "GetCursorInfo");
	queue = (GETQUEUESTATUS) GetProcAddress(user, "GetQueueStatus");

	if (win)
	{
	/* window handle */
	h = win();
	RAND_add(&h, sizeof(h), 0);
	}
	if (cursor)
	{
	/* unfortunately, its not safe to call GetCursorInfo()
	* on NT4 even though it exists in SP3 (or SP6) and
	* higher.
	*/
	if ( osverinfo.dwPlatformId == VER_PLATFORM_WIN32_NT &&
	osverinfo.dwMajorVersion < 5)
	cursor = 0;
	}
	if (cursor)
	{
	/* cursor position */
	/* assume 2 bytes of entropy */
	CURSORINFO ci;
	ci.cbSize = sizeof(CURSORINFO);
	if (cursor(&ci))
	RAND_add(&ci, ci.cbSize, 2);
	}

	if (queue)
	{
	/* message queue status */
	/* assume 1 byte of entropy */
	w = queue(QS_ALLEVENTS);
	RAND_add(&w, sizeof(w), 1);
	}

	FreeLibrary(user);
	}

	/* Toolhelp32 snapshot: enumerate processes, threads, modules and heap
	* http://msdn.microsoft.com/library/psdk/winbase/toolhelp_5pfd.htm
	* (Win 9x and 2000 only, not available on NT)
	*
	* This seeding method was proposed in Peter Gutmann, Software
	* Generation of Practically Strong Random Numbers,
	* http://www.usenix.org/publications/library/proceedings/sec98/gutmann.html
	* revised version at http://www.cryptoengines.com/~peter/06_random.pdf
	* (The assignment of entropy estimates below is arbitrary, but based
	* on Peter's analysis the full poll appears to be safe. Additional
	* interactive seeding is encouraged.)
	*/

	if (kernel)
	{
	CREATETOOLHELP32SNAPSHOT snap;
	HANDLE handle;

	HEAP32FIRST heap_first;
	HEAP32NEXT heap_next;
	HEAP32LIST heaplist_first, heaplist_next;
	PROCESS32 process_first, process_next;
	THREAD32 thread_first, thread_next;
	MODULE32 module_first, module_next;

	HEAPLIST32 hlist;
	HEAPENTRY32 hentry;
	PROCESSENTRY32 p;
	THREADENTRY32 t;
	MODULEENTRY32 m;

	snap = (CREATETOOLHELP32SNAPSHOT)
	GetProcAddress(kernel, "CreateToolhelp32Snapshot");
	heap_first = (HEAP32FIRST) GetProcAddress(kernel, "Heap32First");
	heap_next = (HEAP32NEXT) GetProcAddress(kernel, "Heap32Next");
	heaplist_first = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListFirst");
	heaplist_next = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListNext");
	process_first = (PROCESS32) GetProcAddress(kernel, "Process32First");
	process_next = (PROCESS32) GetProcAddress(kernel, "Process32Next");
	thread_first = (THREAD32) GetProcAddress(kernel, "Thread32First");
	thread_next = (THREAD32) GetProcAddress(kernel, "Thread32Next");
	module_first = (MODULE32) GetProcAddress(kernel, "Module32First");
	module_next = (MODULE32) GetProcAddress(kernel, "Module32Next");

	if (snap && heap_first && heap_next && heaplist_first &&
	heaplist_next && process_first && process_next &&
	thread_first && thread_next && module_first &&
	module_next && (handle = snap(TH32CS_SNAPALL,0))
	!= NULL)
	{
	/* heap list and heap walking */
	/* HEAPLIST32 contains 3 fields that will change with
	* each entry. Consider each field a source of 1 byte
	* of entropy.
	* HEAPENTRY32 contains 5 fields that will change with
	* each entry. Consider each field a source of 1 byte
	* of entropy.
	*/
	hlist.dwSize = sizeof(HEAPLIST32);
	if (heaplist_first(handle, &hlist))
	do
	{
	RAND_add(&hlist, hlist.dwSize, 3);
	hentry.dwSize = sizeof(HEAPENTRY32);
	if (heap_first(&hentry,
	hlist.th32ProcessID,
	hlist.th32HeapID))
	{
	int entrycnt = 80;
	do
	RAND_add(&hentry,
	hentry.dwSize, 5);
	while (heap_next(&hentry)
	&& --entrycnt > 0);
	}
	} while (heaplist_next(handle,
	&hlist));

	/* process walking */
	/* PROCESSENTRY32 contains 9 fields that will change
	* with each entry. Consider each field a source of
	* 1 byte of entropy.
	*/
	p.dwSize = sizeof(PROCESSENTRY32);
	if (process_first(handle, &p))
	do
	RAND_add(&p, p.dwSize, 9);
	while (process_next(handle, &p));

	/* thread walking */
	/* THREADENTRY32 contains 6 fields that will change
	* with each entry. Consider each field a source of
	* 1 byte of entropy.
	*/
	t.dwSize = sizeof(THREADENTRY32);
	if (thread_first(handle, &t))
	do
	RAND_add(&t, t.dwSize, 6);
	while (thread_next(handle, &t));

	/* module walking */
	/* MODULEENTRY32 contains 9 fields that will change
	* with each entry. Consider each field a source of
	* 1 byte of entropy.
	*/
	m.dwSize = sizeof(MODULEENTRY32);
	if (module_first(handle, &m))
	do
	RAND_add(&m, m.dwSize, 9);
	while (module_next(handle, &m));

	CloseHandle(handle);
	}

	FreeLibrary(kernel);
	}

	#ifdef DEBUG
	printf("Exiting RAND_poll\n");
	#endif

	return(1);
	}

	int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam)
	{
	double add_entropy=0;

	switch (iMsg)
	{
	case WM_KEYDOWN:
	{
	static WPARAM key;
	if (key != wParam)
	add_entropy = 0.05;
	key = wParam;
	}
	break;
	case WM_MOUSEMOVE:
	{
	static int lastx,lasty,lastdx,lastdy;
	int x,y,dx,dy;

	x=LOWORD(lParam);
	y=HIWORD(lParam);
	dx=lastx-x;
	dy=lasty-y;
	if (dx != 0 && dy != 0 && dx-lastdx != 0 && dy-lastdy != 0)
	add_entropy=.2;
	lastx=x, lasty=y;
	lastdx=dx, lastdy=dy;
	}
	break;
	}

	readtimer();
	RAND_add(&iMsg, sizeof(iMsg), add_entropy);
	RAND_add(&wParam, sizeof(wParam), 0);
	RAND_add(&lParam, sizeof(lParam), 0);

	return (RAND_status());
	}


	void RAND_screen(void) /* function available for backward compatibility */
	{
	RAND_poll();
	readscreen();
	}


	/* feed timing information to the PRNG */
	static void readtimer(void)
	{
	DWORD w;
	LARGE_INTEGER l;
	static int have_perfc = 1;
	#ifdef _MSC_VER
	static int have_tsc = 1;
	DWORD cyclecount;

	if (have_tsc) {
	__try {
	__asm {
	rdtsc
	mov cyclecount, eax
	}
	RAND_add(&cyclecount, sizeof(cyclecount), 1);
	} __except(EXCEPTION_EXECUTE_HANDLER) {
	have_tsc = 0;
	}
	}
	#else
	# define have_tsc 0
	#endif

	if (have_perfc) {
	if (QueryPerformanceCounter(&l) == 0)
	have_perfc = 0;
	else
	RAND_add(&l, sizeof(l), 0);
	}

	if (!have_tsc && !have_perfc) {
	w = GetTickCount();
	RAND_add(&w, sizeof(w), 0);
	}
	}

	/* feed screen contents to PRNG */
	/*****************************************************************************
	*
	* Created 960901 by Gertjan van Oosten, gertjan@West.NL, West Consulting B.V.
	*
	* Code adapted from
	* <URL:http://www.microsoft.com/kb/developr/win_dk/q97193.htm>;
	* the original copyright message is:
	*
	* (C) Copyright Microsoft Corp. 1993. All rights reserved.
	*
	* You have a royalty-free right to use, modify, reproduce and
	* distribute the Sample Files (and/or any modified version) in
	* any way you find useful, provided that you agree that
	* Microsoft has no warranty obligations or liability for any
	* Sample Application Files which are modified.
	*/

	static void readscreen(void)
	{
	HDC hScrDC; /* screen DC */
	HDC hMemDC; /* memory DC */
	HBITMAP hBitmap; /* handle for our bitmap */
	HBITMAP hOldBitmap; /* handle for previous bitmap */
	BITMAP bm; /* bitmap properties */
	unsigned int size; /* size of bitmap */
	char bmbits; / contents of bitmap */
	int w; /* screen width */
	int h; /* screen height */
	int y; /* y-coordinate of screen lines to grab */
	int n = 16; /* number of screen lines to grab at a time */

	/* Create a screen DC and a memory DC compatible to screen DC */
	hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
	hMemDC = CreateCompatibleDC(hScrDC);

	/* Get screen resolution */
	w = GetDeviceCaps(hScrDC, HORZRES);
	h = GetDeviceCaps(hScrDC, VERTRES);

	/* Create a bitmap compatible with the screen DC */
	hBitmap = CreateCompatibleBitmap(hScrDC, w, n);

	/* Select new bitmap into memory DC */
	hOldBitmap = SelectObject(hMemDC, hBitmap);

	/* Get bitmap properties */
	GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&bm);
	size = (unsigned int)bm.bmWidthBytes * bm.bmHeight * bm.bmPlanes;

	bmbits = OPENSSL_malloc(size);
	if (bmbits) {
	/* Now go through the whole screen, repeatedly grabbing n lines */
	for (y = 0; y < h-n; y += n)
	{
	unsigned char md[MD_DIGEST_LENGTH];

	/* Bitblt screen DC to memory DC */
	BitBlt(hMemDC, 0, 0, w, n, hScrDC, 0, y, SRCCOPY);

	/* Copy bitmap bits from memory DC to bmbits */
	GetBitmapBits(hBitmap, size, bmbits);

	/* Get the hash of the bitmap */
	MD(bmbits,size,md);

	/* Seed the random generator with the hash value */
	RAND_add(md, MD_DIGEST_LENGTH, 0);
	}

	OPENSSL_free(bmbits);
	}

	/* Select old bitmap back into memory DC */
	hBitmap = SelectObject(hMemDC, hOldBitmap);

	/* Clean up */
	DeleteObject(hBitmap);
	DeleteDC(hMemDC);
	DeleteDC(hScrDC);
	}

	#endif