-/*****************************************************************************
- * Initialisation function for the SSL random generator. Takes the contents
- * of the screen as random seed.
- *
- * 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.
- */
-/*
- * I have modified the loading of bytes via RAND_seed() mechanism since
- * the original would have been very very CPU intensive since RAND_seed()
- * does an MD5 per 16 bytes of input. The cost to digest 16 bytes is the same
- * as that to digest 56 bytes. So under the old system, a screen of
- * 1024*768*256 would have been CPU cost of approximately 49,000 56 byte MD5
- * digests or digesting 2.7 mbytes. What I have put in place would
- * be 48 16k MD5 digests, or effectively 48*16+48 MD5 bytes or 816 kbytes
- * or about 3.5 times as much.
- * - eric
- */
-void RAND_screen(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 = 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 MD5 of the bitmap */
- MD(bmbits,size,md);
-
- /* Seed the random generator with the MD5 digest */
- RAND_seed(md, MD_DIGEST_LENGTH);
projects / openssl.git / blobdiff