Windows: Add implementation of ChaCha20 based random generator. Use it for driver need of random bytes (currently only wipe bytes but more to come later).

src/Crypto/chacha256.h

@@ -0,0 +1,31 @@
+#ifndef HEADER_Crypto_ChaCha256
+#define HEADER_Crypto_ChaCha256
+
+#include "Common/Tcdefs.h"
+#include "config.h"
+
+typedef struct
+{
+    CRYPTOPP_ALIGN_DATA(16) uint32 block_[16];
+    CRYPTOPP_ALIGN_DATA(16) uint32 input_[16];
+    size_t pos; 
+    int internalRounds;
+} ChaCha256Ctx;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * key must be 32 bytes long and iv must be 8 bytes long
+ */
+void ChaCha256Init(ChaCha256Ctx* ctx, const unsigned char* key, const unsigned char* iv, int rounds);
+void ChaCha256Encrypt(ChaCha256Ctx* ctx, const unsigned char* in, size_t len, unsigned char* out);
+#define ChaCha256Decrypt ChaCha256Encrypt
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // HEADER_Crypto_ChaCha
+