7 NAMESPACE_BEGIN(CryptoPP)
9 static const
int IDEA_KEYLEN=(6*
IDEA::ROUNDS+4);
11 #define low16(x) ((x)&0xffff) // compiler should be able to optimize this away if word is 16 bits
12 #define high16(x) ((x)>>16)
14 CRYPTOPP_COMPILE_ASSERT(
sizeof(IDEA::Word) >= 2);
17 #define DirectMUL(a,b) \
19 assert(b <= 0xffff); \
21 word32 p=(word32)low16(a)*b; \
25 p = low16(p) - high16(p); \
26 a = (IDEA::Word)p - (IDEA::Word)high16(p); \
32 #ifdef IDEA_LARGECACHE
33 volatile bool IDEA::Base::tablesBuilt =
false;
34 word16 IDEA::Base::log[0x10000];
35 word16 IDEA::Base::antilog[0x10000];
37 void IDEA::Base::BuildLogTables()
48 for (i=0; i<0x10000; i++)
50 antilog[i] = (word16)x;
54 for (i=0; i<0x10000; i++)
55 log[antilog[i]] = (word16)i;
59 void IDEA::Base::LookupKeyLogs()
75 inline void IDEA::Base::LookupMUL(IDEA::Word &a, IDEA::Word b)
77 a = antilog[low16(log[low16(a)]+b)];
79 #endif // IDEA_LARGECACHE
81 void IDEA::Base::UncheckedSetKey(
const byte *userKey,
unsigned int length,
const NameValuePairs &)
83 AssertValidKeyLength(length);
85 #ifdef IDEA_LARGECACHE
91 if (!IsForwardTransformation())
94 #ifdef IDEA_LARGECACHE
99 void IDEA::Base::EnKey (
const byte *userKey)
104 m_key[i] = ((IDEA::Word)userKey[2*i]<<8) | userKey[2*i+1];
106 for (; i<IDEA_KEYLEN; i++)
108 unsigned int j = RoundDownToMultipleOf(i,8U)-8;
109 m_key[i] = low16((m_key[j+(i+1)%8] << 9) | (m_key[j+(i+2)%8] >> 7));
113 static IDEA::Word MulInv(IDEA::Word x)
116 for (
unsigned i=0; i<15; i++)
118 DirectMUL(y,low16(y));
124 static inline IDEA::Word AddInv(IDEA::Word x)
129 void IDEA::Base::DeKey()
134 for (i=0; i<ROUNDS; i++)
136 tempkey[i*6+0] = MulInv(m_key[(ROUNDS-i)*6+0]);
137 tempkey[i*6+1] = AddInv(m_key[(ROUNDS-i)*6+1+(i>0)]);
138 tempkey[i*6+2] = AddInv(m_key[(ROUNDS-i)*6+2-(i>0)]);
139 tempkey[i*6+3] = MulInv(m_key[(ROUNDS-i)*6+3]);
140 tempkey[i*6+4] = m_key[(ROUNDS-1-i)*6+4];
141 tempkey[i*6+5] = m_key[(ROUNDS-1-i)*6+5];
144 tempkey[i*6+0] = MulInv(m_key[(ROUNDS-i)*6+0]);
145 tempkey[i*6+1] = AddInv(m_key[(ROUNDS-i)*6+1]);
146 tempkey[i*6+2] = AddInv(m_key[(ROUNDS-i)*6+2]);
147 tempkey[i*6+3] = MulInv(m_key[(ROUNDS-i)*6+3]);
152 #ifdef IDEA_LARGECACHE
153 #define MUL(a,b) LookupMUL(a,b)
155 #define MUL(a,b) DirectMUL(a,b)
158 void IDEA::Base::ProcessAndXorBlock(
const byte *inBlock,
const byte *xorBlock, byte *outBlock)
const
162 const IDEA::Word *key = m_key;
163 IDEA::Word x0,x1,x2,x3,t0,t1;
164 Block::Get(inBlock)(x0)(x1)(x2)(x3);
166 for (
unsigned int i=0; i<ROUNDS; i++)
184 MUL(x0, key[ROUNDS*6+0]);
185 x2 += key[ROUNDS*6+1];
186 x1 += key[ROUNDS*6+2];
187 MUL(x3, key[ROUNDS*6+3]);
189 Block::Put(xorBlock, outBlock)(x0)(x2)(x1)(x3);