1 files changed, 59 insertions, 0 deletions
diff --git a/CryptoPP/eax.cpp b/CryptoPP/eax.cpp
new file mode 100644
index 000000000..cf836632b
--- /dev/null
+++ b/CryptoPP/eax.cpp
@@ -0,0 +1,59 @@
+// eax.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+#include "eax.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+void EAX_Base::SetKeyWithoutResync(const byte *userKey, size_t keylength, const NameValuePairs &params)
+{
+	AccessMAC().SetKey(userKey, keylength, params);
+	m_buffer.New(2*AccessMAC().TagSize());
+}
+
+void EAX_Base::Resync(const byte *iv, size_t len)
+{
+	MessageAuthenticationCode &mac = AccessMAC();
+	unsigned int blockSize = mac.TagSize();
+
+	memset(m_buffer, 0, blockSize);
+	mac.Update(m_buffer, blockSize);
+	mac.CalculateDigest(m_buffer+blockSize, iv, len);
+
+	m_buffer[blockSize-1] = 1;
+	mac.Update(m_buffer, blockSize);
+
+	m_ctr.SetCipherWithIV(AccessMAC().AccessCipher(), m_buffer+blockSize, blockSize);
+}
+
+size_t EAX_Base::AuthenticateBlocks(const byte *data, size_t len)
+{
+	AccessMAC().Update(data, len);
+	return 0;
+}
+
+void EAX_Base::AuthenticateLastHeaderBlock()
+{
+	assert(m_bufferedDataLength == 0);
+	MessageAuthenticationCode &mac = AccessMAC();
+	unsigned int blockSize = mac.TagSize();
+
+	mac.Final(m_buffer);
+	xorbuf(m_buffer+blockSize, m_buffer, blockSize);
+
+	memset(m_buffer, 0, blockSize);
+	m_buffer[blockSize-1] = 2;
+	mac.Update(m_buffer, blockSize);
+}
+
+void EAX_Base::AuthenticateLastFooterBlock(byte *tag, size_t macSize)
+{
+	assert(m_bufferedDataLength == 0);
+	MessageAuthenticationCode &mac = AccessMAC();
+	unsigned int blockSize = mac.TagSize();
+
+	mac.TruncatedFinal(m_buffer, macSize);
+	xorbuf(tag, m_buffer, m_buffer+blockSize, macSize);
+}
+
+NAMESPACE_END