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-rw-r--r--src/random.cpp48
1 files changed, 47 insertions, 1 deletions
diff --git a/src/random.cpp b/src/random.cpp
index 6155c0d8cf..8ad0a9b007 100644
--- a/src/random.cpp
+++ b/src/random.cpp
@@ -5,9 +5,11 @@
#include "random.h"
+#include "crypto/sha512.h"
#include "support/cleanse.h"
#ifdef WIN32
#include "compat.h" // for Windows API
+#include <wincrypt.h>
#endif
#include "serialize.h" // for begin_ptr(vec)
#include "util.h" // for LogPrint()
@@ -43,7 +45,7 @@ void RandAddSeed()
memory_cleanse((void*)&nCounter, sizeof(nCounter));
}
-void RandAddSeedPerfmon()
+static void RandAddSeedPerfmon()
{
RandAddSeed();
@@ -83,6 +85,29 @@ void RandAddSeedPerfmon()
#endif
}
+/** Get 32 bytes of system entropy. */
+static void GetOSRand(unsigned char *ent32)
+{
+#ifdef WIN32
+ HCRYPTPROV hProvider;
+ int ret = CryptAcquireContextW(&hProvider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT);
+ assert(ret);
+ ret = CryptGenRandom(hProvider, 32, ent32);
+ assert(ret);
+ CryptReleaseContext(hProvider, 0);
+#else
+ int f = open("/dev/urandom", O_RDONLY);
+ assert(f != -1);
+ int have = 0;
+ do {
+ ssize_t n = read(f, ent32 + have, 32 - have);
+ assert(n > 0 && n <= 32 - have);
+ have += n;
+ } while (have < 32);
+ close(f);
+#endif
+}
+
void GetRandBytes(unsigned char* buf, int num)
{
if (RAND_bytes(buf, num) != 1) {
@@ -91,6 +116,27 @@ void GetRandBytes(unsigned char* buf, int num)
}
}
+void GetStrongRandBytes(unsigned char* out, int num)
+{
+ assert(num <= 32);
+ CSHA512 hasher;
+ unsigned char buf[64];
+
+ // First source: OpenSSL's RNG
+ RandAddSeedPerfmon();
+ GetRandBytes(buf, 32);
+ hasher.Write(buf, 32);
+
+ // Second source: OS RNG
+ GetOSRand(buf);
+ hasher.Write(buf, 32);
+
+ // Produce output
+ hasher.Finalize(buf);
+ memcpy(out, buf, num);
+ memory_cleanse(buf, 64);
+}
+
uint64_t GetRand(uint64_t nMax)
{
if (nMax == 0)