8 NAMESPACE_BEGIN(CryptoPP)
12 static inline
unsigned int Mod(
unsigned int c)
14 static const unsigned int modulus = 0x14d;
15 unsigned int c2 = (c<<1) ^ ((c & 0x80) ? modulus : 0);
16 unsigned int c1 = c2 ^ (c>>1) ^ ((c & 1) ? (modulus>>1) : 0);
17 return c | (c1 << 8) | (c2 << 16) | (c1 << 24);
22 static word32 ReedSolomon(word32 high, word32 low)
24 for (
unsigned int i=0; i<8; i++)
26 high = Mod(high>>24) ^ (high<<8) ^ (low>>24);
32 inline word32 Twofish::Base::h0(word32 x,
const word32 *key,
unsigned int kLen)
34 x = x | (x<<8) | (x<<16) | (x<<24);
37 #define Q(a, b, c, d, t) q[a][GETBYTE(t,0)] ^ (q[b][GETBYTE(t,1)] << 8) ^ (q[c][GETBYTE(t,2)] << 16) ^ (q[d][GETBYTE(t,3)] << 24)
38 case 4: x = Q(1, 0, 0, 1, x) ^ key[6];
39 case 3: x = Q(1, 1, 0, 0, x) ^ key[4];
40 case 2: x = Q(0, 1, 0, 1, x) ^ key[2];
41 x = Q(0, 0, 1, 1, x) ^ key[0];
46 inline word32 Twofish::Base::h(word32 x,
const word32 *key,
unsigned int kLen)
49 return mds[0][GETBYTE(x,0)] ^ mds[1][GETBYTE(x,1)] ^ mds[2][GETBYTE(x,2)] ^ mds[3][GETBYTE(x,3)];
52 void Twofish::Base::UncheckedSetKey(
const byte *userKey,
unsigned int keylength,
const NameValuePairs &)
54 AssertValidKeyLength(keylength);
56 unsigned int len = (keylength <= 16 ? 2 : (keylength <= 24 ? 3 : 4));
58 GetUserKey(LITTLE_ENDIAN_ORDER, key.begin(), len*2, userKey, keylength);
63 word32 a = h(i, key, len);
64 word32 b = rotlFixed(h(i+1, key+1, len), 8);
66 m_k[i+1] = rotlFixed(a+2*b, 9);
71 svec[2*(len-i-1)] = ReedSolomon(key[2*i+1], key[2*i]);
74 word32 t = h0(i, svec, len);
75 m_s[0*256+i] = mds[0][GETBYTE(t, 0)];
76 m_s[1*256+i] = mds[1][GETBYTE(t, 1)];
77 m_s[2*256+i] = mds[2][GETBYTE(t, 2)];
78 m_s[3*256+i] = mds[3][GETBYTE(t, 3)];
82 #define G1(x) (m_s[0*256+GETBYTE(x,0)] ^ m_s[1*256+GETBYTE(x,1)] ^ m_s[2*256+GETBYTE(x,2)] ^ m_s[3*256+GETBYTE(x,3)])
83 #define G2(x) (m_s[0*256+GETBYTE(x,3)] ^ m_s[1*256+GETBYTE(x,0)] ^ m_s[2*256+GETBYTE(x,1)] ^ m_s[3*256+GETBYTE(x,2)])
85 #define ENCROUND(n, a, b, c, d) \
86 x = G1 (a); y = G2 (b); \
87 x += y; y += x + k[2 * (n) + 1]; \
88 (c) ^= x + k[2 * (n)]; \
89 (c) = rotrFixed(c, 1); \
90 (d) = rotlFixed(d, 1) ^ y
93 ENCROUND (2 * (n), a, b, c, d); \
94 ENCROUND (2 * (n) + 1, c, d, a, b)
96 #define DECROUND(n, a, b, c, d) \
97 x = G1 (a); y = G2 (b); \
99 (d) ^= y + k[2 * (n) + 1]; \
100 (d) = rotrFixed(d, 1); \
101 (c) = rotlFixed(c, 1); \
102 (c) ^= (x + k[2 * (n)])
104 #define DECCYCLE(n) \
105 DECROUND (2 * (n) + 1, c, d, a, b); \
106 DECROUND (2 * (n), a, b, c, d)
110 void Twofish::Enc::ProcessAndXorBlock(
const byte *inBlock,
const byte *xorBlock, byte *outBlock)
const
112 word32 x, y, a, b, c, d;
114 Block::Get(inBlock)(a)(b)(c)(d);
121 const word32 *k = m_k+8;
139 void Twofish::Dec::ProcessAndXorBlock(
const byte *inBlock,
const byte *xorBlock, byte *outBlock)
const
141 word32 x, y, a, b, c, d;
143 Block::Get(inBlock)(c)(d)(a)(b);
150 const word32 *k = m_k+8;