1 /* crypto/rand/rand_win.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
58 /* ====================================================================
59 * Copyright (c) 1998-2000 The OpenSSL Project. All rights reserved.
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
68 * 2. Redistributions in binary form must reproduce the above copyright
69 * notice, this list of conditions and the following disclaimer in
70 * the documentation and/or other materials provided with the
73 * 3. All advertising materials mentioning features or use of this
74 * software must display the following acknowledgment:
75 * "This product includes software developed by the OpenSSL Project
76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 * endorse or promote products derived from this software without
80 * prior written permission. For written permission, please contact
81 * openssl-core@openssl.org.
83 * 5. Products derived from this software may not be called "OpenSSL"
84 * nor may "OpenSSL" appear in their names without prior written
85 * permission of the OpenSSL Project.
87 * 6. Redistributions of any form whatsoever must retain the following
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com). This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
112 #include "cryptlib.h"
113 #include <openssl/rand.h>
114 #include "rand_lcl.h"
116 #if defined(OPENSSL_SYS_WINDOWS) || defined(OPENSSL_SYS_WIN32)
119 # define _WIN32_WINNT 0x0400
121 #include <wincrypt.h>
122 #include <tlhelp32.h>
124 /* Limit the time spent walking through the heap, processes, threads and modules to
125 a maximum of 1000 miliseconds each, unless CryptoGenRandom failed */
126 #define MAXDELAY 1000
128 /* Intel hardware RNG CSP -- available from
129 * http://developer.intel.com/design/security/rng/redist_license.htm
131 #define PROV_INTEL_SEC 22
132 #define INTEL_DEF_PROV L"Intel Hardware Cryptographic Service Provider"
134 static void readtimer(void);
135 static void readscreen(void);
137 /* It appears like CURSORINFO, PCURSORINFO and LPCURSORINFO are only defined
138 when WINVER is 0x0500 and up, which currently only happens on Win2000.
139 Unfortunately, those are typedefs, so they're a little bit difficult to
140 detect properly. On the other hand, the macro CURSOR_SHOWING is defined
141 within the same conditional, so it can be use to detect the absence of said
144 #ifndef CURSOR_SHOWING
146 * Information about the global cursor.
148 typedef struct tagCURSORINFO
154 } CURSORINFO, *PCURSORINFO, *LPCURSORINFO;
156 #define CURSOR_SHOWING 0x00000001
157 #endif /* CURSOR_SHOWING */
159 typedef BOOL (WINAPI *CRYPTACQUIRECONTEXTW)(HCRYPTPROV *, LPCWSTR, LPCWSTR,
161 typedef BOOL (WINAPI *CRYPTGENRANDOM)(HCRYPTPROV, DWORD, BYTE *);
162 typedef BOOL (WINAPI *CRYPTRELEASECONTEXT)(HCRYPTPROV, DWORD);
164 typedef HWND (WINAPI *GETFOREGROUNDWINDOW)(VOID);
165 typedef BOOL (WINAPI *GETCURSORINFO)(PCURSORINFO);
166 typedef DWORD (WINAPI *GETQUEUESTATUS)(UINT);
168 typedef HANDLE (WINAPI *CREATETOOLHELP32SNAPSHOT)(DWORD, DWORD);
169 typedef BOOL (WINAPI *CLOSETOOLHELP32SNAPSHOT)(HANDLE);
170 typedef BOOL (WINAPI *HEAP32FIRST)(LPHEAPENTRY32, DWORD, ULONG_PTR);
171 typedef BOOL (WINAPI *HEAP32NEXT)(LPHEAPENTRY32);
172 typedef BOOL (WINAPI *HEAP32LIST)(HANDLE, LPHEAPLIST32);
173 typedef BOOL (WINAPI *PROCESS32)(HANDLE, LPPROCESSENTRY32);
174 typedef BOOL (WINAPI *THREAD32)(HANDLE, LPTHREADENTRY32);
175 typedef BOOL (WINAPI *MODULE32)(HANDLE, LPMODULEENTRY32);
178 #ifndef OPENSSL_SYS_WINCE
181 #if 1 /* The NET API is Unicode only. It requires the use of the UNICODE
182 * macro. When UNICODE is defined LPTSTR becomes LPWSTR. LMSTR was
183 * was added to the Platform SDK to allow the NET API to be used in
184 * non-Unicode applications provided that Unicode strings were still
185 * used for input. LMSTR is defined as LPWSTR.
187 typedef NET_API_STATUS (NET_API_FUNCTION * NETSTATGET)
188 (LPWSTR, LPWSTR, DWORD, DWORD, LPBYTE*);
189 typedef NET_API_STATUS (NET_API_FUNCTION * NETFREE)(LPBYTE);
195 HCRYPTPROV hProvider = 0;
200 /* Determine the OS version we are on so we can turn off things
201 * that do not work properly.
203 OSVERSIONINFO osverinfo ;
204 osverinfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO) ;
205 GetVersionEx( &osverinfo ) ;
207 #if defined(OPENSSL_SYS_WINCE)
208 # if defined(_WIN32_WCE) && _WIN32_WCE>=210
209 # ifndef CryptAcquireContext
210 /* reserve for broken header... */
211 # define CryptAcquireContext CryptAcquireContextW
213 /* poll the CryptoAPI PRNG */
214 /* The CryptoAPI returns sizeof(buf) bytes of randomness */
215 if (CryptAcquireContext(&hProvider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))
217 if (CryptGenRandom(hProvider, sizeof(buf), buf))
218 RAND_add(buf, sizeof(buf), sizeof(buf));
219 CryptReleaseContext(hProvider, 0);
222 #else /* OPENSSL_SYS_WINCE */
224 * None of below libraries are present on Windows CE, which is
225 * why we #ifndef the whole section. This also excuses us from
226 * handling the GetProcAddress issue. The trouble is that in
227 * real Win32 API GetProcAddress is available in ANSI flavor
228 * only. In WinCE on the other hand GetProcAddress is a macro
229 * most commonly defined as GetProcAddressW, which accepts
230 * Unicode argument. If we were to call GetProcAddress under
231 * WinCE, I'd recommend to either redefine GetProcAddress as
232 * GetProcAddressA (there seem to be one in common CE spec) or
233 * implement own shim routine, which would accept ANSI argument
234 * and expand it to Unicode.
237 /* load functions dynamically - not available on all systems */
238 HMODULE advapi = LoadLibrary(TEXT("ADVAPI32.DLL"));
239 HMODULE kernel = LoadLibrary(TEXT("KERNEL32.DLL"));
241 HMODULE netapi = LoadLibrary(TEXT("NETAPI32.DLL"));
242 CRYPTACQUIRECONTEXTW acquire = NULL;
243 CRYPTGENRANDOM gen = NULL;
244 CRYPTRELEASECONTEXT release = NULL;
245 NETSTATGET netstatget = NULL;
246 NETFREE netfree = NULL;
250 netstatget = (NETSTATGET) GetProcAddress(netapi,"NetStatisticsGet");
251 netfree = (NETFREE) GetProcAddress(netapi,"NetApiBufferFree");
254 if (netstatget && netfree)
257 /* NetStatisticsGet() is a Unicode only function
258 * STAT_WORKSTATION_0 contains 45 fields and STAT_SERVER_0
259 * contains 17 fields. We treat each field as a source of
260 * one byte of entropy.
263 if (netstatget(NULL, L"LanmanWorkstation", 0, 0, &outbuf) == 0)
265 RAND_add(outbuf, sizeof(STAT_WORKSTATION_0), 45);
268 if (netstatget(NULL, L"LanmanServer", 0, 0, &outbuf) == 0)
270 RAND_add(outbuf, sizeof(STAT_SERVER_0), 17);
278 /* It appears like this can cause an exception deep within ADVAPI32.DLL
279 * at random times on Windows 2000. Reported by Jeffrey Altman.
282 /* Wolfgang Marczy <WMarczy@topcall.co.at> reports that
283 * the RegQueryValueEx call below can hang on NT4.0 (SP6).
284 * So we don't use this at all for now. */
286 if ( osverinfo.dwPlatformId == VER_PLATFORM_WIN32_NT &&
287 osverinfo.dwMajorVersion < 5)
289 /* Read Performance Statistics from NT/2000 registry
290 * The size of the performance data can vary from call
291 * to call so we must guess the size of the buffer to use
292 * and increase its size if we get an ERROR_MORE_DATA
293 * return instead of ERROR_SUCCESS.
295 LONG rc=ERROR_MORE_DATA;
300 while (rc == ERROR_MORE_DATA)
302 buf = realloc(buf,bufsz+8192);
308 rc = RegQueryValueEx(HKEY_PERFORMANCE_DATA, TEXT("Global"),
309 NULL, NULL, buf, &length);
311 if (rc == ERROR_SUCCESS)
313 /* For entropy count assume only least significant
314 * byte of each DWORD is random.
316 RAND_add(&length, sizeof(length), 0);
317 RAND_add(buf, length, length / 4.0);
319 /* Close the Registry Key to allow Windows to cleanup/close
321 * Note: The 'HKEY_PERFORMANCE_DATA' key is implicitly opened
322 * when the RegQueryValueEx above is done. However, if
323 * it is not explicitly closed, it can cause disk
324 * partition manipulation problems.
326 RegCloseKey(HKEY_PERFORMANCE_DATA);
336 * If it's available, then it's available in both ANSI
337 * and UNICODE flavors even in Win9x, documentation says.
338 * We favor Unicode...
340 acquire = (CRYPTACQUIRECONTEXTW) GetProcAddress(advapi,
341 "CryptAcquireContextW");
342 gen = (CRYPTGENRANDOM) GetProcAddress(advapi,
344 release = (CRYPTRELEASECONTEXT) GetProcAddress(advapi,
345 "CryptReleaseContext");
348 if (acquire && gen && release)
350 /* poll the CryptoAPI PRNG */
351 /* The CryptoAPI returns sizeof(buf) bytes of randomness */
352 if (acquire(&hProvider, NULL, NULL, PROV_RSA_FULL,
353 CRYPT_VERIFYCONTEXT))
355 if (gen(hProvider, sizeof(buf), buf) != 0)
357 RAND_add(buf, sizeof(buf), 0);
360 printf("randomness from PROV_RSA_FULL\n");
363 release(hProvider, 0);
366 /* poll the Pentium PRG with CryptoAPI */
367 if (acquire(&hProvider, 0, INTEL_DEF_PROV, PROV_INTEL_SEC, 0))
369 if (gen(hProvider, sizeof(buf), buf) != 0)
371 RAND_add(buf, sizeof(buf), sizeof(buf));
374 printf("randomness from PROV_INTEL_SEC\n");
377 release(hProvider, 0);
384 if ((osverinfo.dwPlatformId != VER_PLATFORM_WIN32_NT ||
385 !OPENSSL_isservice()) &&
386 (user = LoadLibrary(TEXT("USER32.DLL"))))
388 GETCURSORINFO cursor;
389 GETFOREGROUNDWINDOW win;
390 GETQUEUESTATUS queue;
392 win = (GETFOREGROUNDWINDOW) GetProcAddress(user, "GetForegroundWindow");
393 cursor = (GETCURSORINFO) GetProcAddress(user, "GetCursorInfo");
394 queue = (GETQUEUESTATUS) GetProcAddress(user, "GetQueueStatus");
400 RAND_add(&h, sizeof(h), 0);
404 /* unfortunately, its not safe to call GetCursorInfo()
405 * on NT4 even though it exists in SP3 (or SP6) and
408 if ( osverinfo.dwPlatformId == VER_PLATFORM_WIN32_NT &&
409 osverinfo.dwMajorVersion < 5)
414 /* cursor position */
415 /* assume 2 bytes of entropy */
417 ci.cbSize = sizeof(CURSORINFO);
419 RAND_add(&ci, ci.cbSize, 2);
424 /* message queue status */
425 /* assume 1 byte of entropy */
426 w = queue(QS_ALLEVENTS);
427 RAND_add(&w, sizeof(w), 1);
433 /* Toolhelp32 snapshot: enumerate processes, threads, modules and heap
434 * http://msdn.microsoft.com/library/psdk/winbase/toolhelp_5pfd.htm
435 * (Win 9x and 2000 only, not available on NT)
437 * This seeding method was proposed in Peter Gutmann, Software
438 * Generation of Practically Strong Random Numbers,
439 * http://www.usenix.org/publications/library/proceedings/sec98/gutmann.html
440 * revised version at http://www.cryptoengines.com/~peter/06_random.pdf
441 * (The assignment of entropy estimates below is arbitrary, but based
442 * on Peter's analysis the full poll appears to be safe. Additional
443 * interactive seeding is encouraged.)
448 CREATETOOLHELP32SNAPSHOT snap;
449 CLOSETOOLHELP32SNAPSHOT close_snap;
452 HEAP32FIRST heap_first;
453 HEAP32NEXT heap_next;
454 HEAP32LIST heaplist_first, heaplist_next;
455 PROCESS32 process_first, process_next;
456 THREAD32 thread_first, thread_next;
457 MODULE32 module_first, module_next;
466 snap = (CREATETOOLHELP32SNAPSHOT)
467 GetProcAddress(kernel, "CreateToolhelp32Snapshot");
468 close_snap = (CLOSETOOLHELP32SNAPSHOT)
469 GetProcAddress(kernel, "CloseToolhelp32Snapshot");
470 heap_first = (HEAP32FIRST) GetProcAddress(kernel, "Heap32First");
471 heap_next = (HEAP32NEXT) GetProcAddress(kernel, "Heap32Next");
472 heaplist_first = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListFirst");
473 heaplist_next = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListNext");
474 process_first = (PROCESS32) GetProcAddress(kernel, "Process32First");
475 process_next = (PROCESS32) GetProcAddress(kernel, "Process32Next");
476 thread_first = (THREAD32) GetProcAddress(kernel, "Thread32First");
477 thread_next = (THREAD32) GetProcAddress(kernel, "Thread32Next");
478 module_first = (MODULE32) GetProcAddress(kernel, "Module32First");
479 module_next = (MODULE32) GetProcAddress(kernel, "Module32Next");
481 if (snap && heap_first && heap_next && heaplist_first &&
482 heaplist_next && process_first && process_next &&
483 thread_first && thread_next && module_first &&
484 module_next && (handle = snap(TH32CS_SNAPALL,0))
485 != INVALID_HANDLE_VALUE)
487 /* heap list and heap walking */
488 /* HEAPLIST32 contains 3 fields that will change with
489 * each entry. Consider each field a source of 1 byte
491 * HEAPENTRY32 contains 5 fields that will change with
492 * each entry. Consider each field a source of 1 byte
495 hlist.dwSize = sizeof(HEAPLIST32);
496 if (good) stoptime = GetTickCount() + MAXDELAY;
497 if (heaplist_first(handle, &hlist))
500 RAND_add(&hlist, hlist.dwSize, 3);
501 hentry.dwSize = sizeof(HEAPENTRY32);
502 if (heap_first(&hentry,
510 while (heap_next(&hentry)
513 } while (heaplist_next(handle,
514 &hlist) && GetTickCount() < stoptime);
516 /* process walking */
517 /* PROCESSENTRY32 contains 9 fields that will change
518 * with each entry. Consider each field a source of
521 p.dwSize = sizeof(PROCESSENTRY32);
523 if (good) stoptime = GetTickCount() + MAXDELAY;
524 if (process_first(handle, &p))
526 RAND_add(&p, p.dwSize, 9);
527 while (process_next(handle, &p) && GetTickCount() < stoptime);
530 /* THREADENTRY32 contains 6 fields that will change
531 * with each entry. Consider each field a source of
534 t.dwSize = sizeof(THREADENTRY32);
535 if (good) stoptime = GetTickCount() + MAXDELAY;
536 if (thread_first(handle, &t))
538 RAND_add(&t, t.dwSize, 6);
539 while (thread_next(handle, &t) && GetTickCount() < stoptime);
542 /* MODULEENTRY32 contains 9 fields that will change
543 * with each entry. Consider each field a source of
546 m.dwSize = sizeof(MODULEENTRY32);
547 if (good) stoptime = GetTickCount() + MAXDELAY;
548 if (module_first(handle, &m))
550 RAND_add(&m, m.dwSize, 9);
551 while (module_next(handle, &m)
552 && (GetTickCount() < stoptime));
563 #endif /* !OPENSSL_SYS_WINCE */
568 /* memory usage statistics */
569 GlobalMemoryStatus(&m);
570 RAND_add(&m, sizeof(m), 1);
573 w = GetCurrentProcessId();
574 RAND_add(&w, sizeof(w), 1);
577 printf("Exiting RAND_poll\n");
583 int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam)
585 double add_entropy=0;
599 static int lastx,lasty,lastdx,lastdy;
606 if (dx != 0 && dy != 0 && dx-lastdx != 0 && dy-lastdy != 0)
609 lastdx=dx, lastdy=dy;
615 RAND_add(&iMsg, sizeof(iMsg), add_entropy);
616 RAND_add(&wParam, sizeof(wParam), 0);
617 RAND_add(&lParam, sizeof(lParam), 0);
619 return (RAND_status());
623 void RAND_screen(void) /* function available for backward compatibility */
630 /* feed timing information to the PRNG */
631 static void readtimer(void)
635 static int have_perfc = 1;
636 #if defined(_MSC_VER) && defined(_M_X86)
637 static int have_tsc = 1;
647 RAND_add(&cyclecount, sizeof(cyclecount), 1);
648 } __except(EXCEPTION_EXECUTE_HANDLER) {
657 if (QueryPerformanceCounter(&l) == 0)
660 RAND_add(&l, sizeof(l), 0);
663 if (!have_tsc && !have_perfc) {
665 RAND_add(&w, sizeof(w), 0);
669 /* feed screen contents to PRNG */
670 /*****************************************************************************
672 * Created 960901 by Gertjan van Oosten, gertjan@West.NL, West Consulting B.V.
675 * <URL:http://support.microsoft.com/default.aspx?scid=kb;[LN];97193>;
676 * the original copyright message is:
678 * (C) Copyright Microsoft Corp. 1993. All rights reserved.
680 * You have a royalty-free right to use, modify, reproduce and
681 * distribute the Sample Files (and/or any modified version) in
682 * any way you find useful, provided that you agree that
683 * Microsoft has no warranty obligations or liability for any
684 * Sample Application Files which are modified.
687 static void readscreen(void)
689 #if !defined(OPENSSL_SYS_WINCE) && !defined(OPENSSL_SYS_WIN32_CYGWIN)
690 HDC hScrDC; /* screen DC */
691 HDC hMemDC; /* memory DC */
692 HBITMAP hBitmap; /* handle for our bitmap */
693 HBITMAP hOldBitmap; /* handle for previous bitmap */
694 BITMAP bm; /* bitmap properties */
695 unsigned int size; /* size of bitmap */
696 char *bmbits; /* contents of bitmap */
697 int w; /* screen width */
698 int h; /* screen height */
699 int y; /* y-coordinate of screen lines to grab */
700 int n = 16; /* number of screen lines to grab at a time */
702 if (GetVersion() >= 0x80000000 || !OPENSSL_isservice())
705 /* Create a screen DC and a memory DC compatible to screen DC */
706 hScrDC = CreateDC(TEXT("DISPLAY"), NULL, NULL, NULL);
707 hMemDC = CreateCompatibleDC(hScrDC);
709 /* Get screen resolution */
710 w = GetDeviceCaps(hScrDC, HORZRES);
711 h = GetDeviceCaps(hScrDC, VERTRES);
713 /* Create a bitmap compatible with the screen DC */
714 hBitmap = CreateCompatibleBitmap(hScrDC, w, n);
716 /* Select new bitmap into memory DC */
717 hOldBitmap = SelectObject(hMemDC, hBitmap);
719 /* Get bitmap properties */
720 GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&bm);
721 size = (unsigned int)bm.bmWidthBytes * bm.bmHeight * bm.bmPlanes;
723 bmbits = OPENSSL_malloc(size);
725 /* Now go through the whole screen, repeatedly grabbing n lines */
726 for (y = 0; y < h-n; y += n)
728 unsigned char md[MD_DIGEST_LENGTH];
730 /* Bitblt screen DC to memory DC */
731 BitBlt(hMemDC, 0, 0, w, n, hScrDC, 0, y, SRCCOPY);
733 /* Copy bitmap bits from memory DC to bmbits */
734 GetBitmapBits(hBitmap, size, bmbits);
736 /* Get the hash of the bitmap */
739 /* Seed the random generator with the hash value */
740 RAND_add(md, MD_DIGEST_LENGTH, 0);
743 OPENSSL_free(bmbits);
746 /* Select old bitmap back into memory DC */
747 hBitmap = SelectObject(hMemDC, hOldBitmap);
750 DeleteObject(hBitmap);
753 #endif /* !OPENSSL_SYS_WINCE */