1 files changed, 106 insertions, 0 deletions

diff --git a/lib/cryptopp/gcm.h b/lib/cryptopp/gcm.h
new file mode 100644
index 000000000..272a51c9c
--- /dev/null
+++ b/lib/cryptopp/gcm.h
@@ -0,0 +1,106 @@
+#ifndef CRYPTOPP_GCM_H
+#define CRYPTOPP_GCM_H
+
+#include "authenc.h"
+#include "modes.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+//! .
+enum GCM_TablesOption {GCM_2K_Tables, GCM_64K_Tables};
+
+//! .
+class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE GCM_Base : public AuthenticatedSymmetricCipherBase
+{
+public:
+	// AuthenticatedSymmetricCipher
+	std::string AlgorithmName() const
+		{return GetBlockCipher().AlgorithmName() + std::string("/GCM");}
+	size_t MinKeyLength() const
+		{return GetBlockCipher().MinKeyLength();}
+	size_t MaxKeyLength() const
+		{return GetBlockCipher().MaxKeyLength();}
+	size_t DefaultKeyLength() const
+		{return GetBlockCipher().DefaultKeyLength();}
+	size_t GetValidKeyLength(size_t n) const
+		{return GetBlockCipher().GetValidKeyLength(n);}
+	bool IsValidKeyLength(size_t n) const
+		{return GetBlockCipher().IsValidKeyLength(n);}
+	unsigned int OptimalDataAlignment() const;
+	IV_Requirement IVRequirement() const
+		{return UNIQUE_IV;}
+	unsigned int IVSize() const
+		{return 12;}
+	unsigned int MinIVLength() const
+		{return 1;}
+	unsigned int MaxIVLength() const
+		{return UINT_MAX;}		// (W64LIT(1)<<61)-1 in the standard
+	unsigned int DigestSize() const
+		{return 16;}
+	lword MaxHeaderLength() const
+		{return (W64LIT(1)<<61)-1;}
+	lword MaxMessageLength() const
+		{return ((W64LIT(1)<<39)-256)/8;}
+
+protected:
+	// AuthenticatedSymmetricCipherBase
+	bool AuthenticationIsOnPlaintext() const
+		{return false;}
+	unsigned int AuthenticationBlockSize() const
+		{return HASH_BLOCKSIZE;}
+	void SetKeyWithoutResync(const byte *userKey, size_t keylength, const NameValuePairs &params);
+	void Resync(const byte *iv, size_t len);
+	size_t AuthenticateBlocks(const byte *data, size_t len);
+	void AuthenticateLastHeaderBlock();
+	void AuthenticateLastConfidentialBlock();
+	void AuthenticateLastFooterBlock(byte *mac, size_t macSize);
+	SymmetricCipher & AccessSymmetricCipher() {return m_ctr;}
+
+	virtual BlockCipher & AccessBlockCipher() =0;
+	virtual GCM_TablesOption GetTablesOption() const =0;
+
+	const BlockCipher & GetBlockCipher() const {return const_cast<GCM_Base *>(this)->AccessBlockCipher();};
+	byte *HashBuffer() {return m_buffer+REQUIRED_BLOCKSIZE;}
+	byte *HashKey() {return m_buffer+2*REQUIRED_BLOCKSIZE;}
+	byte *MulTable() {return m_buffer+3*REQUIRED_BLOCKSIZE;}
+	inline void ReverseHashBufferIfNeeded();
+
+	class CRYPTOPP_DLL GCTR : public CTR_Mode_ExternalCipher::Encryption
+	{
+	protected:
+		void IncrementCounterBy256();
+	};
+
+	GCTR m_ctr;
+	static word16 s_reductionTable[256];
+	static volatile bool s_reductionTableInitialized;
+	enum {REQUIRED_BLOCKSIZE = 16, HASH_BLOCKSIZE = 16};
+};
+
+//! .
+template <class T_BlockCipher, GCM_TablesOption T_TablesOption, bool T_IsEncryption>
+class GCM_Final : public GCM_Base
+{
+public:
+	static std::string StaticAlgorithmName()
+		{return T_BlockCipher::StaticAlgorithmName() + std::string("/GCM");}
+	bool IsForwardTransformation() const
+		{return T_IsEncryption;}
+
+private:
+	GCM_TablesOption GetTablesOption() const {return T_TablesOption;}
+	BlockCipher & AccessBlockCipher() {return m_cipher;}
+	typename T_BlockCipher::Encryption m_cipher;
+};
+
+//! <a href="http://www.cryptolounge.org/wiki/GCM">GCM</a>
+template <class T_BlockCipher, GCM_TablesOption T_TablesOption=GCM_2K_Tables>
+struct GCM : public AuthenticatedSymmetricCipherDocumentation
+{
+	typedef GCM_Final<T_BlockCipher, T_TablesOption, true> Encryption;
+	typedef GCM_Final<T_BlockCipher, T_TablesOption, false> Decryption;
+};
+
+NAMESPACE_END
+
+#endif