00001 #ifndef CRYPTOPP_GCM_H
00002 #define CRYPTOPP_GCM_H
00003
00004 #include "authenc.h"
00005 #include "modes.h"
00006
00007 NAMESPACE_BEGIN(CryptoPP)
00008
00009
00010 enum GCM_TablesOption {GCM_2K_Tables, GCM_64K_Tables};
00011
00012
00013 class CRYPTOPP_DLL CRYPTOPP_NO_VTABLE GCM_Base : public AuthenticatedSymmetricCipherBase
00014 {
00015 public:
00016
00017 std::string AlgorithmName() const
00018 {return GetBlockCipher().AlgorithmName() + std::string("/GCM");}
00019 size_t MinKeyLength() const
00020 {return GetBlockCipher().MinKeyLength();}
00021 size_t MaxKeyLength() const
00022 {return GetBlockCipher().MaxKeyLength();}
00023 size_t DefaultKeyLength() const
00024 {return GetBlockCipher().DefaultKeyLength();}
00025 size_t GetValidKeyLength(size_t n) const
00026 {return GetBlockCipher().GetValidKeyLength(n);}
00027 bool IsValidKeyLength(size_t n) const
00028 {return GetBlockCipher().IsValidKeyLength(n);}
00029 unsigned int OptimalDataAlignment() const;
00030 IV_Requirement IVRequirement() const
00031 {return UNIQUE_IV;}
00032 unsigned int IVSize() const
00033 {return 12;}
00034 unsigned int MinIVLength() const
00035 {return 1;}
00036 unsigned int MaxIVLength() const
00037 {return UINT_MAX;}
00038 unsigned int DigestSize() const
00039 {return 16;}
00040 lword MaxHeaderLength() const
00041 {return (W64LIT(1)<<61)-1;}
00042 lword MaxMessageLength() const
00043 {return ((W64LIT(1)<<39)-256)/8;}
00044
00045 protected:
00046
00047 bool AuthenticationIsOnPlaintext() const
00048 {return false;}
00049 unsigned int AuthenticationBlockSize() const
00050 {return HASH_BLOCKSIZE;}
00051 void SetKeyWithoutResync(const byte *userKey, size_t keylength, const NameValuePairs ¶ms);
00052 void Resync(const byte *iv, size_t len);
00053 size_t AuthenticateBlocks(const byte *data, size_t len);
00054 void AuthenticateLastHeaderBlock();
00055 void AuthenticateLastConfidentialBlock();
00056 void AuthenticateLastFooterBlock(byte *mac, size_t macSize);
00057 SymmetricCipher & AccessSymmetricCipher() {return m_ctr;}
00058
00059 virtual BlockCipher & AccessBlockCipher() =0;
00060 virtual GCM_TablesOption GetTablesOption() const =0;
00061
00062 const BlockCipher & GetBlockCipher() const {return const_cast<GCM_Base *>(this)->AccessBlockCipher();};
00063 byte *HashBuffer() {return m_buffer+REQUIRED_BLOCKSIZE;}
00064 byte *HashKey() {return m_buffer+2*REQUIRED_BLOCKSIZE;}
00065 byte *MulTable() {return m_buffer+3*REQUIRED_BLOCKSIZE;}
00066
00067 class GCTR : public CTR_Mode_ExternalCipher::Encryption
00068 {
00069 protected:
00070 void IncrementCounterBy256();
00071 };
00072
00073 GCTR m_ctr;
00074 static word16 s_reductionTable[256];
00075 static bool s_reductionTableInitialized;
00076 enum {REQUIRED_BLOCKSIZE = 16, HASH_BLOCKSIZE = 16};
00077 };
00078
00079
00080 template <class T_BlockCipher, GCM_TablesOption T_TablesOption, bool T_IsEncryption>
00081 class GCM_Final : public GCM_Base
00082 {
00083 public:
00084 static std::string StaticAlgorithmName()
00085 {return T_BlockCipher::StaticAlgorithmName() + std::string("/GCM");}
00086 bool IsForwardTransformation() const
00087 {return T_IsEncryption;}
00088
00089 private:
00090 GCM_TablesOption GetTablesOption() const {return T_TablesOption;}
00091 BlockCipher & AccessBlockCipher() {return m_cipher;}
00092 typename T_BlockCipher::Encryption m_cipher;
00093 };
00094
00095
00096 template <class T_BlockCipher, GCM_TablesOption T_TablesOption=GCM_2K_Tables>
00097 struct GCM : public AuthenticatedSymmetricCipherDocumentation
00098 {
00099 typedef GCM_Final<T_BlockCipher, T_TablesOption, true> Encryption;
00100 typedef GCM_Final<T_BlockCipher, T_TablesOption, false> Decryption;
00101 };
00102
00103 NAMESPACE_END
00104
00105 #endif