From 99f8ce096bc5569adbfea1911dbcda24c28d8d8b Mon Sep 17 00:00:00 2001
From: Ben Summers <ben@fluffy.co.uk>
Date: Fri, 14 Oct 2005 08:50:54 +0000
Subject: Box Backup 0.09 with a few tweeks

---
 lib/crypto/Random.cpp | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100755 lib/crypto/Random.cpp

(limited to 'lib/crypto/Random.cpp')

diff --git a/lib/crypto/Random.cpp b/lib/crypto/Random.cpp
new file mode 100755
index 00000000..3df5fc5e
--- /dev/null
+++ b/lib/crypto/Random.cpp
@@ -0,0 +1,127 @@
+// --------------------------------------------------------------------------
+//
+// File
+//		Name:    Random.cpp
+//		Purpose: Random numbers
+//		Created: 31/12/03
+//
+// --------------------------------------------------------------------------
+
+#include "Box.h"
+
+#include <openssl/rand.h>
+#include <stdio.h>
+
+#include "Random.h"
+#include "CipherException.h"
+
+#include "MemLeakFindOn.h"
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    Random::Initialise()
+//		Purpose: Add additional randomness to the standard library initialisation
+//		Created: 18/6/04
+//
+// --------------------------------------------------------------------------
+void Random::Initialise()
+{
+#ifndef PLATFORM_RANDOM_DEVICE_NONE
+	if(::RAND_load_file(PLATFORM_RANDOM_DEVICE, 1024) != 1024)
+	{
+		THROW_EXCEPTION(CipherException, RandomInitFailed)
+	}
+#else
+	::fprintf(stderr, "No random device -- additional seeding of random number generator not performed.\n");
+#endif
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    Random::Generate(void *, int)
+//		Purpose: Generate Length bytes of random data
+//		Created: 31/12/03
+//
+// --------------------------------------------------------------------------
+void Random::Generate(void *pOutput, int Length)
+{
+	if(RAND_pseudo_bytes((uint8_t*)pOutput, Length) == -1)
+	{
+		THROW_EXCEPTION(CipherException, PseudoRandNotAvailable)
+	}
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    Random::GenerateHex(int)
+//		Purpose: Generate Length bytes of hex encoded data. Note that the
+//				 maximum length requested is limited. (Returns a string
+//				 2 x Length characters long.)
+//		Created: 1/11/04
+//
+// --------------------------------------------------------------------------
+std::string Random::GenerateHex(int Length)
+{
+	uint8_t r[256];
+	if(Length > sizeof(r))
+	{
+		THROW_EXCEPTION(CipherException, LengthRequestedTooLongForRandomHex)
+	}
+	Random::Generate(r, Length);
+	
+	std::string o;
+	static const char *h = "0123456789abcdef";
+	for(int l = 0; l < Length; ++l)
+	{
+		o += h[r[l] >> 4];
+		o += h[r[l] & 0xf];
+	}
+	
+	return o;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+//		Name:    Random::RandomInt(int)
+//		Purpose: Return a random integer between 0 and MaxValue inclusive.
+//		Created: 21/1/04
+//
+// --------------------------------------------------------------------------
+uint32_t Random::RandomInt(uint32_t MaxValue)
+{
+	uint32_t v = 0;
+
+	// Generate a mask
+	uint32_t mask = 0;
+	while(mask < MaxValue)
+	{
+		mask = (mask << 1) | 1;
+	}
+
+	do
+	{
+		// Generate a random number
+		uint32_t r = 0;
+		Random::Generate(&r, sizeof(r));
+		
+		// Mask off relevant bits
+		v = r & mask;
+		
+		// Check that it's in the right range.
+	} while(v > MaxValue);
+	
+	// NOTE: don't do a mod, because this doesn't give a correct random distribution
+	
+	return v;
+}
+
+
+
-- 
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