void RC5::Base::UncheckedSetKey(const byte *k, unsigned int keylen, const NameValuePairs ¶ms)
{
AssertValidKeyLength(keylen);
r = GetRoundsAndThrowIfInvalid(params, this);
sTable.New(2*(r+1));
static const RC5_WORD MAGIC_P = 0xb7e15163L; // magic constant P for wordsize
static const RC5_WORD MAGIC_Q = 0x9e3779b9L; // magic constant Q for wordsize
static const int U=sizeof(RC5_WORD);
const unsigned int c = STDMAX((keylen+U-1)/U, 1U); // RC6 paper says c=1 if keylen==0
SecBlock<RC5_WORD> l(c);
GetUserKey(LITTLE_ENDIAN_ORDER, l.begin(), c, k, keylen);
sTable[0] = MAGIC_P;
for (unsigned j=1; j<sTable.size(); j++)
sTable[j] = sTable[j-1] + MAGIC_Q;
RC5_WORD a=0, b=0;
const unsigned n = 3*STDMAX((unsigned int)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));
}
}
void SHARK::Base::UncheckedSetKey(const byte *key, unsigned int keyLen, const NameValuePairs ¶ms)
{
AssertValidKeyLength(keyLen);
m_rounds = GetRoundsAndThrowIfInvalid(params, this);
m_roundKeys.New(m_rounds+1);
// concatenate key enought times to fill a
for (unsigned int i=0; i<(m_rounds+1)*8; i++)
((byte *)m_roundKeys.begin())[i] = key[i%keyLen];
SHARK::Encryption e;
e.InitForKeySetup();
byte IV[8] = {0,0,0,0,0,0,0,0};
CFB_Mode_ExternalCipher::Encryption cfb(e, IV);
cfb.ProcessString((byte *)m_roundKeys.begin(), (m_rounds+1)*8);
ConditionalByteReverse(BIG_ENDIAN_ORDER, m_roundKeys.begin(), m_roundKeys.begin(), (m_rounds+1)*8);
m_roundKeys[m_rounds] = SHARKTransform(m_roundKeys[m_rounds]);
if (!IsForwardTransformation())
{
unsigned int i;
// transform encryption round keys into decryption round keys
for (i=0; i<m_rounds/2; i++)
std::swap(m_roundKeys[i], m_roundKeys[m_rounds-i]);
for (i=1; i<m_rounds; i++)
m_roundKeys[i] = SHARKTransform(m_roundKeys[i]);
}
#ifdef IS_LITTLE_ENDIAN
m_roundKeys[0] = ByteReverse(m_roundKeys[0]);
m_roundKeys[m_rounds] = ByteReverse(m_roundKeys[m_rounds]);
#endif
}
