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 #if !defined(OPENSSL_SYS_WINCE)
160 typedef BOOL (WINAPI *CRYPTACQUIRECONTEXTW)(HCRYPTPROV *, LPCWSTR, LPCWSTR,
162 typedef BOOL (WINAPI *CRYPTGENRANDOM)(HCRYPTPROV, DWORD, BYTE *);
163 typedef BOOL (WINAPI *CRYPTRELEASECONTEXT)(HCRYPTPROV, DWORD);
165 typedef HWND (WINAPI *GETFOREGROUNDWINDOW)(VOID);
166 typedef BOOL (WINAPI *GETCURSORINFO)(PCURSORINFO);
167 typedef DWORD (WINAPI *GETQUEUESTATUS)(UINT);
169 typedef HANDLE (WINAPI *CREATETOOLHELP32SNAPSHOT)(DWORD, DWORD);
170 typedef BOOL (WINAPI *CLOSETOOLHELP32SNAPSHOT)(HANDLE);
171 typedef BOOL (WINAPI *HEAP32FIRST)(LPHEAPENTRY32, DWORD, size_t);
172 typedef BOOL (WINAPI *HEAP32NEXT)(LPHEAPENTRY32);
173 typedef BOOL (WINAPI *HEAP32LIST)(HANDLE, LPHEAPLIST32);
174 typedef BOOL (WINAPI *PROCESS32)(HANDLE, LPPROCESSENTRY32);
175 typedef BOOL (WINAPI *THREAD32)(HANDLE, LPTHREADENTRY32);
176 typedef BOOL (WINAPI *MODULE32)(HANDLE, LPMODULEENTRY32);
181 /* 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);
191 #endif /* !OPENSSL_SYS_WINCE */
196 HCRYPTPROV hProvider = 0;
201 #if defined(OPENSSL_SYS_WINCE)
202 # if defined(_WIN32_WCE) && _WIN32_WCE>=300
203 /* Even though MSDN says _WIN32_WCE>=210, it doesn't seem to be available
204 * in commonly available implementations prior 300... */
207 /* poll the CryptoAPI PRNG */
208 /* The CryptoAPI returns sizeof(buf) bytes of randomness */
209 if (CryptAcquireContextW(&hProvider, NULL, NULL, PROV_RSA_FULL,
210 CRYPT_VERIFYCONTEXT))
212 if (CryptGenRandom(hProvider, sizeof(buf), buf))
213 RAND_add(buf, sizeof(buf), sizeof(buf));
214 CryptReleaseContext(hProvider, 0);
218 #else /* OPENSSL_SYS_WINCE */
220 * None of below libraries are present on Windows CE, which is
221 * why we #ifndef the whole section. This also excuses us from
222 * handling the GetProcAddress issue. The trouble is that in
223 * real Win32 API GetProcAddress is available in ANSI flavor
224 * only. In WinCE on the other hand GetProcAddress is a macro
225 * most commonly defined as GetProcAddressW, which accepts
226 * Unicode argument. If we were to call GetProcAddress under
227 * WinCE, I'd recommend to either redefine GetProcAddress as
228 * GetProcAddressA (there seem to be one in common CE spec) or
229 * implement own shim routine, which would accept ANSI argument
230 * and expand it to Unicode.
233 /* load functions dynamically - not available on all systems */
234 HMODULE advapi = LoadLibrary(TEXT("ADVAPI32.DLL"));
235 HMODULE kernel = LoadLibrary(TEXT("KERNEL32.DLL"));
237 HMODULE netapi = LoadLibrary(TEXT("NETAPI32.DLL"));
238 CRYPTACQUIRECONTEXTW acquire = NULL;
239 CRYPTGENRANDOM gen = NULL;
240 CRYPTRELEASECONTEXT release = NULL;
241 NETSTATGET netstatget = NULL;
242 NETFREE netfree = NULL;
247 netstatget = (NETSTATGET) GetProcAddress(netapi,"NetStatisticsGet");
248 netfree = (NETFREE) GetProcAddress(netapi,"NetApiBufferFree");
251 if (netstatget && netfree)
254 /* NetStatisticsGet() is a Unicode only function
255 * STAT_WORKSTATION_0 contains 45 fields and STAT_SERVER_0
256 * contains 17 fields. We treat each field as a source of
257 * one byte of entropy.
260 if (netstatget(NULL, L"LanmanWorkstation", 0, 0, &outbuf) == 0)
262 RAND_add(outbuf, sizeof(STAT_WORKSTATION_0), 45);
265 if (netstatget(NULL, L"LanmanServer", 0, 0, &outbuf) == 0)
267 RAND_add(outbuf, sizeof(STAT_SERVER_0), 17);
275 /* It appears like this can cause an exception deep within ADVAPI32.DLL
276 * at random times on Windows 2000. Reported by Jeffrey Altman.
283 * If it's available, then it's available in both ANSI
284 * and UNICODE flavors even in Win9x, documentation says.
285 * We favor Unicode...
287 acquire = (CRYPTACQUIRECONTEXTW) GetProcAddress(advapi,
288 "CryptAcquireContextW");
289 gen = (CRYPTGENRANDOM) GetProcAddress(advapi,
291 release = (CRYPTRELEASECONTEXT) GetProcAddress(advapi,
292 "CryptReleaseContext");
295 if (acquire && gen && release)
297 /* poll the CryptoAPI PRNG */
298 /* The CryptoAPI returns sizeof(buf) bytes of randomness */
299 if (acquire(&hProvider, NULL, NULL, PROV_RSA_FULL,
300 CRYPT_VERIFYCONTEXT))
302 if (gen(hProvider, sizeof(buf), buf) != 0)
304 RAND_add(buf, sizeof(buf), 0);
307 printf("randomness from PROV_RSA_FULL\n");
310 release(hProvider, 0);
313 /* poll the Pentium PRG with CryptoAPI */
314 if (acquire(&hProvider, 0, INTEL_DEF_PROV, PROV_INTEL_SEC, 0))
316 if (gen(hProvider, sizeof(buf), buf) != 0)
318 RAND_add(buf, sizeof(buf), sizeof(buf));
321 printf("randomness from PROV_INTEL_SEC\n");
324 release(hProvider, 0);
331 if ((!check_winnt() ||
332 !OPENSSL_isservice()) &&
333 (user = LoadLibrary(TEXT("USER32.DLL"))))
335 GETCURSORINFO cursor;
336 GETFOREGROUNDWINDOW win;
337 GETQUEUESTATUS queue;
339 win = (GETFOREGROUNDWINDOW) GetProcAddress(user, "GetForegroundWindow");
340 cursor = (GETCURSORINFO) GetProcAddress(user, "GetCursorInfo");
341 queue = (GETQUEUESTATUS) GetProcAddress(user, "GetQueueStatus");
347 RAND_add(&h, sizeof(h), 0);
351 /* unfortunately, its not safe to call GetCursorInfo()
352 * on NT4 even though it exists in SP3 (or SP6) and
355 if (check_winnt() && !check_win_minplat(5))
360 /* cursor position */
361 /* assume 2 bytes of entropy */
363 ci.cbSize = sizeof(CURSORINFO);
365 RAND_add(&ci, ci.cbSize, 2);
370 /* message queue status */
371 /* assume 1 byte of entropy */
372 w = queue(QS_ALLEVENTS);
373 RAND_add(&w, sizeof(w), 1);
380 * Toolhelp32 snapshot: enumerate processes, threads, modules and heap
381 * http://msdn.microsoft.com/library/psdk/winbase/toolhelp_5pfd.htm
382 * (Win 9x and 2000 only, not available on NT)
384 * This seeding method was proposed in Peter Gutmann, Software
385 * Generation of Practically Strong Random Numbers,
386 * http://www.usenix.org/publications/library/proceedings/sec98/gutmann.html
387 * revised version at http://www.cryptoengines.com/~peter/06_random.pdf
388 * (The assignment of entropy estimates below is arbitrary, but based
389 * on Peter's analysis the full poll appears to be safe. Additional
390 * interactive seeding is encouraged.)
395 CREATETOOLHELP32SNAPSHOT snap;
396 CLOSETOOLHELP32SNAPSHOT close_snap;
399 HEAP32FIRST heap_first;
400 HEAP32NEXT heap_next;
401 HEAP32LIST heaplist_first, heaplist_next;
402 PROCESS32 process_first, process_next;
403 THREAD32 thread_first, thread_next;
404 MODULE32 module_first, module_next;
413 snap = (CREATETOOLHELP32SNAPSHOT)
414 GetProcAddress(kernel, "CreateToolhelp32Snapshot");
415 close_snap = (CLOSETOOLHELP32SNAPSHOT)
416 GetProcAddress(kernel, "CloseToolhelp32Snapshot");
417 heap_first = (HEAP32FIRST) GetProcAddress(kernel, "Heap32First");
418 heap_next = (HEAP32NEXT) GetProcAddress(kernel, "Heap32Next");
419 heaplist_first = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListFirst");
420 heaplist_next = (HEAP32LIST) GetProcAddress(kernel, "Heap32ListNext");
421 process_first = (PROCESS32) GetProcAddress(kernel, "Process32First");
422 process_next = (PROCESS32) GetProcAddress(kernel, "Process32Next");
423 thread_first = (THREAD32) GetProcAddress(kernel, "Thread32First");
424 thread_next = (THREAD32) GetProcAddress(kernel, "Thread32Next");
425 module_first = (MODULE32) GetProcAddress(kernel, "Module32First");
426 module_next = (MODULE32) GetProcAddress(kernel, "Module32Next");
428 if (snap && heap_first && heap_next && heaplist_first &&
429 heaplist_next && process_first && process_next &&
430 thread_first && thread_next && module_first &&
431 module_next && (handle = snap(TH32CS_SNAPALL,0))
432 != INVALID_HANDLE_VALUE)
434 /* heap list and heap walking */
435 /* HEAPLIST32 contains 3 fields that will change with
436 * each entry. Consider each field a source of 1 byte
438 * HEAPENTRY32 contains 5 fields that will change with
439 * each entry. Consider each field a source of 1 byte
442 ZeroMemory(&hlist, sizeof(HEAPLIST32));
443 hlist.dwSize = sizeof(HEAPLIST32);
444 if (good) starttime = GetTickCount();
446 if (heaplist_first(handle, &hlist))
449 following discussion on dev ML, exception on WinCE (or other Win
450 platform) is theoretically of unknown origin; prevent infinite
451 loop here when this theoretical case occurs; otherwise cope with
452 the expected (MSDN documented) exception-throwing behaviour of
453 Heap32Next() on WinCE.
455 based on patch in original message by Tanguy Fautré (2009/03/02)
456 Subject: RAND_poll() and CreateToolhelp32Snapshot() stability
458 int ex_cnt_limit = 42;
461 RAND_add(&hlist, hlist.dwSize, 3);
464 ZeroMemory(&hentry, sizeof(HEAPENTRY32));
465 hentry.dwSize = sizeof(HEAPENTRY32);
466 if (heap_first(&hentry,
474 while (heap_next(&hentry)
475 && (!good || (GetTickCount()-starttime)<MAXDELAY)
479 __except (EXCEPTION_EXECUTE_HANDLER)
481 /* ignore access violations when walking the heap list */
484 } while (heaplist_next(handle, &hlist)
485 && (!good || (GetTickCount()-starttime)<MAXDELAY)
486 && ex_cnt_limit > 0);
490 if (heaplist_first(handle, &hlist))
494 RAND_add(&hlist, hlist.dwSize, 3);
495 hentry.dwSize = sizeof(HEAPENTRY32);
496 if (heap_first(&hentry,
504 while (heap_next(&hentry)
507 } while (heaplist_next(handle, &hlist)
508 && (!good || (GetTickCount()-starttime)<MAXDELAY));
512 /* process walking */
513 /* PROCESSENTRY32 contains 9 fields that will change
514 * with each entry. Consider each field a source of
517 p.dwSize = sizeof(PROCESSENTRY32);
519 if (good) starttime = GetTickCount();
520 if (process_first(handle, &p))
522 RAND_add(&p, p.dwSize, 9);
523 while (process_next(handle, &p) && (!good || (GetTickCount()-starttime)<MAXDELAY));
526 /* THREADENTRY32 contains 6 fields that will change
527 * with each entry. Consider each field a source of
530 t.dwSize = sizeof(THREADENTRY32);
531 if (good) starttime = GetTickCount();
532 if (thread_first(handle, &t))
534 RAND_add(&t, t.dwSize, 6);
535 while (thread_next(handle, &t) && (!good || (GetTickCount()-starttime)<MAXDELAY));
538 /* MODULEENTRY32 contains 9 fields that will change
539 * with each entry. Consider each field a source of
542 m.dwSize = sizeof(MODULEENTRY32);
543 if (good) starttime = GetTickCount();
544 if (module_first(handle, &m))
546 RAND_add(&m, m.dwSize, 9);
547 while (module_next(handle, &m)
548 && (!good || (GetTickCount()-starttime)<MAXDELAY));
559 #endif /* !OPENSSL_SYS_WINCE */
564 /* memory usage statistics */
565 GlobalMemoryStatus(&m);
566 RAND_add(&m, sizeof(m), 1);
569 w = GetCurrentProcessId();
570 RAND_add(&w, sizeof(w), 1);
573 printf("Exiting RAND_poll\n");
579 int RAND_event(UINT iMsg, WPARAM wParam, LPARAM lParam)
581 double add_entropy=0;
595 static int lastx,lasty,lastdx,lastdy;
602 if (dx != 0 && dy != 0 && dx-lastdx != 0 && dy-lastdy != 0)
605 lastdx=dx, lastdy=dy;
611 RAND_add(&iMsg, sizeof(iMsg), add_entropy);
612 RAND_add(&wParam, sizeof(wParam), 0);
613 RAND_add(&lParam, sizeof(lParam), 0);
615 return (RAND_status());
619 void RAND_screen(void) /* function available for backward compatibility */
626 /* feed timing information to the PRNG */
627 static void readtimer(void)
631 static int have_perfc = 1;
632 #if defined(_MSC_VER) && defined(_M_X86)
633 static int have_tsc = 1;
643 RAND_add(&cyclecount, sizeof(cyclecount), 1);
644 } __except(EXCEPTION_EXECUTE_HANDLER) {
653 if (QueryPerformanceCounter(&l) == 0)
656 RAND_add(&l, sizeof(l), 0);
659 if (!have_tsc && !have_perfc) {
661 RAND_add(&w, sizeof(w), 0);
665 /* feed screen contents to PRNG */
666 /*****************************************************************************
668 * Created 960901 by Gertjan van Oosten, gertjan@West.NL, West Consulting B.V.
671 * <URL:http://support.microsoft.com/default.aspx?scid=kb;[LN];97193>;
672 * the original copyright message is:
674 * (C) Copyright Microsoft Corp. 1993. All rights reserved.
676 * You have a royalty-free right to use, modify, reproduce and
677 * distribute the Sample Files (and/or any modified version) in
678 * any way you find useful, provided that you agree that
679 * Microsoft has no warranty obligations or liability for any
680 * Sample Application Files which are modified.
683 static void readscreen(void)
685 #if !defined(OPENSSL_SYS_WINCE) && !defined(OPENSSL_SYS_WIN32_CYGWIN)
686 HDC hScrDC; /* screen DC */
687 HDC hMemDC; /* memory DC */
688 HBITMAP hBitmap; /* handle for our bitmap */
689 HBITMAP hOldBitmap; /* handle for previous bitmap */
690 BITMAP bm; /* bitmap properties */
691 unsigned int size; /* size of bitmap */
692 char *bmbits; /* contents of bitmap */
693 int w; /* screen width */
694 int h; /* screen height */
695 int y; /* y-coordinate of screen lines to grab */
696 int n = 16; /* number of screen lines to grab at a time */
698 if (check_winnt() && OPENSSL_isservice()>0)
701 /* Create a screen DC and a memory DC compatible to screen DC */
702 hScrDC = CreateDC(TEXT("DISPLAY"), NULL, NULL, NULL);
703 hMemDC = CreateCompatibleDC(hScrDC);
705 /* Get screen resolution */
706 w = GetDeviceCaps(hScrDC, HORZRES);
707 h = GetDeviceCaps(hScrDC, VERTRES);
709 /* Create a bitmap compatible with the screen DC */
710 hBitmap = CreateCompatibleBitmap(hScrDC, w, n);
712 /* Select new bitmap into memory DC */
713 hOldBitmap = SelectObject(hMemDC, hBitmap);
715 /* Get bitmap properties */
716 GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&bm);
717 size = (unsigned int)bm.bmWidthBytes * bm.bmHeight * bm.bmPlanes;
719 bmbits = OPENSSL_malloc(size);
721 /* Now go through the whole screen, repeatedly grabbing n lines */
722 for (y = 0; y < h-n; y += n)
724 unsigned char md[MD_DIGEST_LENGTH];
726 /* Bitblt screen DC to memory DC */
727 BitBlt(hMemDC, 0, 0, w, n, hScrDC, 0, y, SRCCOPY);
729 /* Copy bitmap bits from memory DC to bmbits */
730 GetBitmapBits(hBitmap, size, bmbits);
732 /* Get the hash of the bitmap */
735 /* Seed the random generator with the hash value */
736 RAND_add(md, MD_DIGEST_LENGTH, 0);
739 OPENSSL_free(bmbits);
742 /* Select old bitmap back into memory DC */
743 hBitmap = SelectObject(hMemDC, hOldBitmap);
746 DeleteObject(hBitmap);
749 #endif /* !OPENSSL_SYS_WINCE */