Initial revision

git-svn-id: svn://svn.code.sf.net/p/cryptopp/code/trunk/c5@2 57ff6487-cd31-0410-9ec3-f628ee90f5f0

1 files changed, 100 insertions, 0 deletions

diff --git a/randpool.cpp b/randpool.cpp
new file mode 100644
index 0000000..9fa0b4b
--- /dev/null
+++ b/randpool.cpp
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+// randpool.cpp - written and placed in the public domain by Wei Dai
+// The algorithm in this module comes from PGP's randpool.c
+
+#include "pch.h"
+#include "randpool.h"
+#include "mdc.h"
+#include "sha.h"
+#include "modes.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+typedef MDC<SHA> RandomPoolCipher;
+
+RandomPool::RandomPool(unsigned int poolSize)
+	: pool(poolSize), key(RandomPoolCipher::DEFAULT_KEYLENGTH)
+{
+	assert(poolSize > key.size());
+
+	addPos=0;
+	getPos=poolSize;
+	memset(pool, 0, poolSize);
+	memset(key, 0, key.size());
+}
+
+void RandomPool::Stir()
+{
+	CFB_Mode<RandomPoolCipher>::Encryption cipher;
+
+	for (int i=0; i<2; i++)
+	{
+		cipher.SetKeyWithIV(key, key.size(), pool.end()-cipher.IVSize());
+		cipher.ProcessString(pool, pool.size());
+		memcpy(key, pool, key.size());
+	}
+
+	addPos = 0;
+	getPos = key.size();
+}
+
+unsigned int RandomPool::Put2(const byte *inString, unsigned int length, int messageEnd, bool blocking)
+{
+	unsigned t;
+
+	while (length > (t = pool.size() - addPos))
+	{
+		xorbuf(pool+addPos, inString, t);
+		inString += t;
+		length -= t;
+		Stir();
+	}
+
+	if (length)
+	{
+		xorbuf(pool+addPos, inString, length);
+		addPos += length;
+		getPos = pool.size(); // Force stir on get
+	}
+
+	return 0;
+}
+
+unsigned int RandomPool::TransferTo2(BufferedTransformation &target, unsigned long &transferBytes, const std::string &channel, bool blocking)
+{
+	if (!blocking)
+		throw NotImplemented("RandomPool: nonblocking transfer is not implemented by this object");
+
+	unsigned int t;
+	unsigned long size = transferBytes;
+
+	while (size > (t = pool.size() - getPos))
+	{
+		target.ChannelPut(channel, pool+getPos, t);
+		size -= t;
+		Stir();
+	}
+
+	if (size)
+	{
+		target.ChannelPut(channel, pool+getPos, size);
+		getPos += size;
+	}
+
+	return 0;
+}
+
+byte RandomPool::GenerateByte()
+{
+	if (getPos == pool.size())
+		Stir();
+
+	return pool[getPos++];
+}
+
+void RandomPool::GenerateBlock(byte *outString, unsigned int size)
+{
+	ArraySink sink(outString, size);
+	TransferTo(sink, size);
+}
+
+NAMESPACE_END