1 files changed, 63 insertions, 0 deletions
diff --git a/CryptoPP/randpool.cpp b/CryptoPP/randpool.cpp
new file mode 100644
index 000000000..a063c8996
--- /dev/null
+++ b/CryptoPP/randpool.cpp
@@ -0,0 +1,63 @@
+// randpool.cpp - written and placed in the public domain by Wei Dai
+// RandomPool used to follow the design of randpool in PGP 2.6.x,
+// but as of version 5.5 it has been redesigned to reduce the risk
+// of reusing random numbers after state rollback (which may occur
+// when running in a virtual machine like VMware).
+
+#include "pch.h"
+
+#ifndef CRYPTOPP_IMPORTS
+
+#include "randpool.h"
+#include "aes.h"
+#include "sha.h"
+#include "hrtimer.h"
+#include <time.h>
+
+NAMESPACE_BEGIN(CryptoPP)
+
+RandomPool::RandomPool()
+	: m_pCipher(new AES::Encryption), m_keySet(false)
+{
+	memset(m_key, 0, m_key.SizeInBytes());
+	memset(m_seed, 0, m_seed.SizeInBytes());
+}
+
+void RandomPool::IncorporateEntropy(const byte *input, size_t length)
+{
+	SHA256 hash;
+	hash.Update(m_key, 32);
+	hash.Update(input, length);
+	hash.Final(m_key);
+	m_keySet = false;
+}
+
+void RandomPool::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
+{
+	if (size > 0)
+	{
+		if (!m_keySet)
+			m_pCipher->SetKey(m_key, 32);
+
+		Timer timer;
+		TimerWord tw = timer.GetCurrentTimerValue();
+		CRYPTOPP_COMPILE_ASSERT(sizeof(tw) <= 16);
+		*(TimerWord *)m_seed.data() += tw;
+
+		time_t t = time(NULL);
+		CRYPTOPP_COMPILE_ASSERT(sizeof(t) <= 8);
+		*(time_t *)(m_seed.data()+8) += t;
+
+		do
+		{
+			m_pCipher->ProcessBlock(m_seed);
+			size_t len = UnsignedMin(16, size);
+			target.ChannelPut(channel, m_seed, len);
+			size -= len;
+		} while (size > 0);
+	}
+}
+
+NAMESPACE_END
+
+#endif