RC6Base::RC6Base(const byte *k, unsigned int keylen, unsigned int rounds)
: r(rounds), sTable((2*r)+4)
{
assert(keylen == KeyLength(keylen));
static const RC6_WORD MAGIC_P = 0xb7e15163L; // magic constant P for wordsize
static const RC6_WORD MAGIC_Q = 0x9e3779b9L; // magic constant Q for wordsize
static const int U=sizeof(RC6_WORD);
const unsigned int c=(keylen-1)/U + 1;
SecBlock<RC6_WORD> l(c);
GetUserKeyLittleEndian(l.ptr, c, k, keylen);
sTable[0] = MAGIC_P;
for (unsigned j=1; j<sTable.size;j++)
sTable[j] = sTable[j-1] + MAGIC_Q;
RC6_WORD a=0, b=0;
const unsigned n = 3*STDMAX(sTable.size,c);
for (unsigned h=0; h < n; h++)
{
a = sTable[h % sTable.size] = rotlFixed((sTable[h % sTable.size] + a + b), 3);
b = l[h % c] = rotlMod((l[h % c] + a + b), (a+b));
}
}
Rijndael::Rijndael(const byte *userKey, unsigned int keylen)
: k_len(keylen/4), key(k_len*5 + 24)
{
assert(keylen == KeyLength(keylen));
word32 t;
int i;
GetUserKeyLittleEndian(key.ptr, k_len, userKey, keylen);
switch(k_len)
{
case 4: t = key[3];
for(i = 0; i < 10; ++i)
{
t = rotrFixed(t, 8);
t = ls_box(t) ^ rco_tab[i];
key[4 * i + 4] = t ^= key[4 * i];
key[4 * i + 5] = t ^= key[4 * i + 1];
key[4 * i + 6] = t ^= key[4 * i + 2];
key[4 * i + 7] = t ^= key[4 * i + 3];
}
break;
case 6: t = key[5];
for(i = 0; i < 8; ++i)
{
t = rotrFixed(t, 8);
t = ls_box(t) ^ rco_tab[i];
key[6 * i + 6] = t ^= key[6 * i];
key[6 * i + 7] = t ^= key[6 * i + 1];
key[6 * i + 8] = t ^= key[6 * i + 2];
key[6 * i + 9] = t ^= key[6 * i + 3];
key[6 * i + 10] = t ^= key[6 * i + 4];
key[6 * i + 11] = t ^= key[6 * i + 5];
}
break;
case 8: t = key[7];
for(i = 0; i < 7; ++i)
{
t = rotrFixed(t, 8);
t = ls_box(t) ^ rco_tab[i];
key[8 * i + 8] = t ^= key[8 * i];
key[8 * i + 9] = t ^= key[8 * i + 1];
key[8 * i + 10] = t ^= key[8 * i + 2];
key[8 * i + 11] = t ^= key[8 * i + 3];
key[8 * i + 12] = t = key[8 * i + 4] ^ ls_box(t); \
key[8 * i + 13] = t ^= key[8 * i + 5];
key[8 * i + 14] = t ^= key[8 * i + 6];
key[8 * i + 15] = t ^= key[8 * i + 7];
}
break;
}
}
