win32: use bcrypt for random generators

The API is available since Vista and is also available in winstore app. We
don't have to support 2 different versions anymore in 4.0.

configure.ac

@@ -1298,12 +1298,6 @@ AS_IF([test "${enable_ssp}" != "no" -a "${enable_optimizations}" != "no"], [
   ])
 ])
 
-AS_IF([test "${SYS}" = "mingw32"], [
-    dnl library for BCrypt APIs
-    AS_IF([test "${vlc_winstore_app}" = 1],
-          VLC_ADD_LIBS([libvlccore], [-lbcrypt]))
-])
-
 VLC_SAVE_FLAGS
 LDFLAGS="${LDFLAGS} -Wl,-Bsymbolic"
 AC_CACHE_CHECK([if linker supports -Bsymbolic], [ac_cv_ld_bsymbolic], [

src/Makefile.am

@@ -418,6 +418,7 @@ libvlccore_la_SOURCES += posix/timer.c win32/dirs-uap.c
 else
 libvlccore_la_SOURCES += win32/timer.c win32/dirs.c
 endif
+libvlccore_la_LIBADD += -lbcrypt
 endif
 
 if HAVE_OS2

src/win32/rand.c

@@ -25,15 +25,10 @@
 #include <vlc_common.h>
 #include <vlc_rand.h>
 
-#ifdef VLC_WINSTORE_APP
-# include <bcrypt.h>
-#else
-# include <wincrypt.h>
-#endif
+#include <bcrypt.h>
 
 void vlc_rand_bytes (void *buf, size_t len)
 {
-#ifdef VLC_WINSTORE_APP
     BCRYPT_ALG_HANDLE algo_handle;
     NTSTATUS ret = BCryptOpenAlgorithmProvider(&algo_handle, BCRYPT_RNG_ALGORITHM,
                                                MS_PRIMITIVE_PROVIDER, 0);
@@ -42,39 +37,4 @@ void vlc_rand_bytes (void *buf, size_t len)
         BCryptGenRandom(algo_handle, buf, len, 0);
         BCryptCloseAlgorithmProvider(algo_handle, 0);
     }
-#else
-    size_t count = len;
-    uint8_t *p_buf = (uint8_t *)buf;
-
-    /* fill buffer with pseudo-random data */
-    while (count > 0)
-    {
-        unsigned int val;
-        val = rand();
-        if (count < sizeof (val))
-        {
-            memcpy (p_buf, &val, count);
-            break;
-        }
-
-        memcpy (p_buf, &val, sizeof (val));
-        count -= sizeof (val);
-        p_buf += sizeof (val);
-    }
-
-    HCRYPTPROV hProv;
-    /* acquire default encryption context */
-    if( CryptAcquireContext(
-        &hProv,                 // Variable to hold returned handle.
-        NULL,                   // Use default key container.
-        MS_DEF_PROV,            // Use default CSP.
-        PROV_RSA_FULL,          // Type of provider to acquire.
-        CRYPT_VERIFYCONTEXT) )  // Flag values
-    {
-        /* fill buffer with pseudo-random data, initial buffer content
-           is used as auxiliary random seed */
-        CryptGenRandom(hProv, len, buf);
-        CryptReleaseContext(hProv, 0);
-    }
-#endif /* VLC_WINSTORE_APP */
 }