commit afc77c3ca22407cf4304bec23e3490705e7cb912
parent 16ef369c8820b15a8d559d314149efaf0216f00a
Author: Michael Savage <mikejsavage@gmail.com>
Date: Sat, 13 Mar 2021 13:49:47 +0200
Use BCryptGenRandom on Windows
Diffstat:
2 files changed, 4 insertions(+), 15 deletions(-)
diff --git a/README.md b/README.md
@@ -59,7 +59,7 @@ ggentropy uses the following functionality:
| OS | Implementation |
| - | - |
-| Windows | [CryptGenRandom](https://docs.microsoft.com/en-us/windows/win32/api/wincrypt/nf-wincrypt-cryptgenrandom) |
+| Windows | [BCryptGenRandom](https://docs.microsoft.com/en-us/windows/win32/api/bcrypt/nf-bcrypt-bcryptgenrandom) |
| MacOS | [getentropy](https://opensource.apple.com/source/xnu/xnu-3789.21.4/bsd/man/man2/getentropy.2.auto.html) |
| Linux | [getrandom](https://lwn.net/Articles/606141/) with a fallback to /dev/urandom if the syscall doesn't exist |
| FreeBSD/OpenBSD/NetBSD | [arc4random_buf](https://man.openbsd.org/arc4random_buf) |
diff --git a/ggentropy.cpp b/ggentropy.cpp
@@ -66,26 +66,15 @@ static bool try_urandom( void * buf, size_t n ) {
#if PLATFORM_WINDOWS
-#pragma comment( lib, "advapi32.lib" )
+#pragma comment( lib, "bcrypt.lib" )
-#ifndef WIN32_LEAN_AND_MEAN
#define WIN32_LEAN_AND_MEAN
-#endif
-
#include <windows.h>
-#include <wincrypt.h>
+#include <bcrypt.h>
bool ggentropy( void * buf, size_t n ) {
assert( n <= 256 );
-
- HCRYPTPROV provider;
- if( CryptAcquireContext( &provider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT ) == 0 )
- return false;
-
- int ok = CryptGenRandom( provider, n, ( BYTE * ) buf );
- CryptReleaseContext( provider, 0 );
-
- return ok != 0;
+ return !FAILED( BCryptGenRandom( NULL, ( PUCHAR ) buf, n, BCRYPT_USE_SYSTEM_PREFERRED_RNG ) );
}
#elif PLATFORM_LINUX
