public void InitializeKey(byte[] key, int offset)
{
uint i, c, d, t, s, shifts;
c = CipherUtil.GetIntLE(key, offset + 0);
d = CipherUtil.GetIntLE(key, offset + 4);
t = ((d >> 4) ^ c) & 0x0f0f0f0f;
c ^= t;
d ^= t << 4;
t = (((c << (16 - (-2))) ^ c) & 0xcccc0000);
c = c ^ t ^ (t >> (16 - (-2)));
t = (((d << (16 - (-2))) ^ d) & 0xcccc0000);
d = d ^ t ^ (t >> (16 - (-2)));
t = ((d >> 1) ^ c) & 0x55555555;
c ^= t;
d ^= t << 1;
t = ((c >> 8) ^ d) & 0x00ff00ff;
d ^= t;
c ^= t << 8;
t = ((d >> 1) ^ c) & 0x55555555;
c ^= t;
d ^= t << 1;
d = ((d & 0xff) << 16) | (d & 0xff00) |
((d >> 16) & 0xff) | ((c >> 4) & 0xf000000);
c &= 0x0fffffff;
shifts = 0x7efc;
for (i = 0; i < 16; i++)
{
if ((shifts & 1) != 0)
{
c = ((c >> 2) | (c << 26));
d = ((d >> 2) | (d << 26));
}
else
{
c = ((c >> 1) | (c << 27));
d = ((d >> 1) | (d << 27));
}
shifts >>= 1;
c &= 0x0fffffff;
d &= 0x0fffffff;
s = SKB[0, (c) & 0x3f] |
SKB[1, ((c >> 6) & 0x03) | ((c >> 7) & 0x3c)] |
SKB[2, ((c >> 13) & 0x0f) | ((c >> 14) & 0x30)] |
SKB[3, ((c >> 20) & 0x01) | ((c >> 21) & 0x06) | ((c >> 22) & 0x38)];
t = SKB[4, (d) & 0x3f] |
SKB[5, ((d >> 7) & 0x03) | ((d >> 8) & 0x3c)] |
SKB[6, (d >> 15) & 0x3f] |
SKB[7, ((d >> 21) & 0x0f) | ((d >> 22) & 0x30)];
_key[i * 2] = ((t << 16) | (s & 0xffff));
s = ((s >> 16) | (t & 0xffff0000));
_key[(i * 2) + 1] = (s << 4) | (s >> 28);
}
}
public void BlockDecrypt(byte[] input, int inOffset, byte[] output, int outOffset)
{
uint t;
int i;
uint[] lr = new uint[2];
lr[0] = CipherUtil.GetIntLE(input, inOffset);
lr[1] = CipherUtil.GetIntLE(input, inOffset + 4);
initPerm(lr);
t = (lr[1] << 1) | (lr[1] >> 31);
lr[1] = (lr[0] << 1) | (lr[0] >> 31);
lr[0] = t;
for (i = 30; i > 0; i -= 4)
{
desCipher1(lr, i);
desCipher2(lr, i - 2);
}
lr[0] = (lr[0] >> 1) | (lr[0] << 31);
lr[1] = (lr[1] >> 1) | (lr[1] << 31);
finalPerm(lr);
CipherUtil.PutIntLE(lr[0], output, outOffset);
CipherUtil.PutIntLE(lr[1], output, outOffset + 4);
}