Get entropy from the windows system provider and give to SSL

src/PlatRand.cpp

@@ -0,0 +1,38 @@
+
+#ifdef WIN32
+
+#include <windows.h>
+#include <wincrypt.h>
+
+#include <openssl/rand.h>
+
+bool AddSystemEntropy()
+{ // Get entropy from the Windows crypto provider
+	char name[512], rand[128];
+	DWORD count = 500;
+	HCRYPTOPROV cryptoHandle;
+
+	if (!CryptGetDefaultProvider(PROV_RSA_FULL, NULL, CRYPT_MACHINE_DEFAULT, name, &count))
+		return false;
+	if (!CryptAcquireContext(&cryptoHandle, NULL, name, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT | CRYPT_SILENT))
+		return false;
+
+	if(!CryptGenRandom(cryptoHandle, 128, reinterpret_cast<BYTE*> rand))
+	{
+		CryptReleaseContext(cryptoHandle, 0);
+		return false;
+	}
+
+	CryptReleaseContext(cryptoHandle, 0);
+	RAND_seed(rand, 128);
+	return true;
+}
+
+#else
+
+bool AddSystemEntropy()
+{ // Stub for implementing on other platforms
+	return false;
+}
+
+#endif