1 files changed, 86 insertions, 0 deletions
diff --git a/embeddedcryptopp/hmac.cpp b/embeddedcryptopp/hmac.cpp
new file mode 100644
index 0000000..d4a649c
--- /dev/null
+++ b/embeddedcryptopp/hmac.cpp
@@ -0,0 +1,86 @@
+// hmac.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+
+#ifndef CRYPTOPP_IMPORTS
+
+#include "hmac.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+void HMAC_Base::UncheckedSetKey(const byte *userKey, unsigned int keylength, const NameValuePairs &)
+{
+	AssertValidKeyLength(keylength);
+
+	Restart();
+
+	HashTransformation &hash = AccessHash();
+	unsigned int blockSize = hash.BlockSize();
+
+	if (!blockSize)
+		throw InvalidArgument("HMAC: can only be used with a block-based hash function");
+
+	m_buf.resize(2*AccessHash().BlockSize() + AccessHash().DigestSize());
+
+	if (keylength <= blockSize)
+		memcpy(AccessIpad(), userKey, keylength);
+	else
+	{
+		AccessHash().CalculateDigest(AccessIpad(), userKey, keylength);
+		keylength = hash.DigestSize();
+	}
+
+	assert(keylength <= blockSize);
+	memset(AccessIpad()+keylength, 0, blockSize-keylength);
+
+	for (unsigned int i=0; i<blockSize; i++)
+	{
+		AccessOpad()[i] = AccessIpad()[i] ^ 0x5c;
+		AccessIpad()[i] ^= 0x36;
+	}
+}
+
+void HMAC_Base::KeyInnerHash()
+{
+	assert(!m_innerHashKeyed);
+	HashTransformation &hash = AccessHash();
+	hash.Update(AccessIpad(), hash.BlockSize());
+	m_innerHashKeyed = true;
+}
+
+void HMAC_Base::Restart()
+{
+	if (m_innerHashKeyed)
+	{
+		AccessHash().Restart();
+		m_innerHashKeyed = false;
+	}
+}
+
+void HMAC_Base::Update(const byte *input, size_t length)
+{
+	if (!m_innerHashKeyed)
+		KeyInnerHash();
+	AccessHash().Update(input, length);
+}
+
+void HMAC_Base::TruncatedFinal(byte *mac, size_t size)
+{
+	ThrowIfInvalidTruncatedSize(size);
+
+	HashTransformation &hash = AccessHash();
+
+	if (!m_innerHashKeyed)
+		KeyInnerHash();
+	hash.Final(AccessInnerHash());
+
+	hash.Update(AccessOpad(), hash.BlockSize());
+	hash.Update(AccessInnerHash(), hash.DigestSize());
+	hash.TruncatedFinal(mac, size);
+
+	m_innerHashKeyed = false;
+}
+
+NAMESPACE_END
+
+#endif