/// <remarks>
/// Expand the key and set state variables
/// </remarks>
private UInt32[] ExpandKey(byte[] Key, bool Encryption)
{
// block and key in 32 bit words
_wrdBlocks = _blockSize / 4;
// expanded key size
int keySize = _wrdBlocks * (_dfnRounds + 1);
// hkdf return array
int keyBytes = keySize * 4;
byte[] rawKey = new byte[keyBytes];
int saltSize = Key.Length - _ikmSize;
// salt must be divisible of hash blocksize
if (saltSize % _keyEngine.BlockSize != 0)
saltSize = saltSize - saltSize % _keyEngine.BlockSize;
// hkdf input
byte[] hkdfKey = new byte[_ikmSize];
byte[] hkdfSalt = new byte[saltSize];
// copy hkdf key and salt from user key
Buffer.BlockCopy(Key, 0, hkdfKey, 0, _ikmSize);
Buffer.BlockCopy(Key, _ikmSize, hkdfSalt, 0, saltSize);
// HKDF generator expands array using an SHA512 HMAC
using (HKDF gen = new HKDF(_keyEngine, false))
{
gen.Initialize(hkdfSalt, hkdfKey, _hkdfInfo);
gen.Generate(rawKey);
}
// initialize working key
UInt32[] wK = new UInt32[keySize];
// copy bytes to working key
Buffer.BlockCopy(rawKey, 0, wK, 0, keyBytes);
// inverse cipher
if (!Encryption)
{
// reverse key
for (int i = 0, k = keySize - _wrdBlocks; i < k; i += _wrdBlocks, k -= _wrdBlocks)
{
for (int j = 0; j < _wrdBlocks; j++)
{
UInt32 temp = wK[i + j];
wK[i + j] = wK[k + j];
wK[k + j] = temp;
}
}
// sbox inversion
for (int i = _wrdBlocks; i < keySize - _wrdBlocks; i++)
{
wK[i] = IT0[SBox[(wK[i] >> 24)]] ^
IT1[SBox[(byte)(wK[i] >> 16)]] ^
IT2[SBox[(byte)(wK[i] >> 8)]] ^
IT3[SBox[(byte)wK[i]]];
}
}
return wK;
}
private Int32[] ExpandKey(byte[] Key)
{
Int32 Y0, Y1, Y2, Y3;
int k64Cnt = 8;
int keyCtr = 0;
int keySize = _dfnRounds * 2 + 8;
int kbtSize = keySize * 4;
byte[] rawKey = new byte[kbtSize];
byte[] sbKey = new byte[32];
Int32[] eKm = new Int32[k64Cnt];
Int32[] oKm = new Int32[k64Cnt];
Int32[] wK = new Int32[keySize];
int saltSize = Key.Length - _ikmSize;
// salt must be divisible of hash blocksize
if (saltSize % _keyEngine.BlockSize != 0)
saltSize = saltSize - saltSize % _keyEngine.BlockSize;
// hkdf input
byte[] hkdfKey = new byte[_ikmSize];
byte[] hkdfSalt = new byte[saltSize];
// copy hkdf key and salt from user key
Buffer.BlockCopy(Key, 0, hkdfKey, 0, _ikmSize);
Buffer.BlockCopy(Key, _ikmSize, hkdfSalt, 0, saltSize);
// HKDF generator expands array using an SHA512 HMAC
using (HKDF gen = new HKDF(_keyEngine, false))
{
gen.Initialize(hkdfSalt, hkdfKey, _hkdfInfo);
gen.Generate(rawKey);
}
// copy bytes to working key
Buffer.BlockCopy(rawKey, 0, wK, 0, kbtSize);
for (int i = 0; i < k64Cnt; i++)
{
// round key material
eKm[i] = BytesToInt32(rawKey, keyCtr);
keyCtr += 4;
oKm[i] = BytesToInt32(rawKey, keyCtr);
keyCtr += 4;
// sbox key material
Int32ToBytes(MDSEncode(eKm[i], oKm[i]), sbKey, ((4 * k64Cnt) - 4) - (i * 4));
}
keyCtr = 0;
// create keyed sbox
while (keyCtr < KEY_BITS)
{
Y0 = Y1 = Y2 = Y3 = keyCtr;
Y0 = (byte)Q1[Y0] ^ sbKey[28];
Y1 = (byte)Q0[Y1] ^ sbKey[29];
Y2 = (byte)Q0[Y2] ^ sbKey[30];
Y3 = (byte)Q1[Y3] ^ sbKey[31];
Y0 = (byte)Q1[Y0] ^ sbKey[24];
Y1 = (byte)Q1[Y1] ^ sbKey[25];
Y2 = (byte)Q0[Y2] ^ sbKey[26];
Y3 = (byte)Q0[Y3] ^ sbKey[27];
Y0 = (byte)Q0[Y0] ^ sbKey[20];
Y1 = (byte)Q1[Y1] ^ sbKey[21];
Y2 = (byte)Q1[Y2] ^ sbKey[22];
Y3 = (byte)Q0[Y3] ^ sbKey[23];
Y0 = (byte)Q0[Y0] ^ sbKey[16];
Y1 = (byte)Q0[Y1] ^ sbKey[17];
Y2 = (byte)Q1[Y2] ^ sbKey[18];
Y3 = (byte)Q1[Y3] ^ sbKey[19];
Y0 = (byte)Q1[Y0] ^ sbKey[12];
Y1 = (byte)Q0[Y1] ^ sbKey[13];
Y2 = (byte)Q0[Y2] ^ sbKey[14];
Y3 = (byte)Q1[Y3] ^ sbKey[15];
Y0 = (byte)Q1[Y0] ^ sbKey[8];
Y1 = (byte)Q1[Y1] ^ sbKey[9];
Y2 = (byte)Q0[Y2] ^ sbKey[10];
Y3 = (byte)Q0[Y3] ^ sbKey[11];
// sbox members as MDS matrix multiplies
_sprBox[keyCtr * 2] = MDS0[(byte)Q0[(byte)Q0[Y0] ^ sbKey[4]] ^ sbKey[0]];
_sprBox[keyCtr * 2 + 1] = MDS1[(byte)Q0[Q1[Y1] ^ sbKey[5]] ^ sbKey[1]];
_sprBox[(keyCtr * 2) + 0x200] = MDS2[(byte)Q1[(byte)Q0[Y2] ^ sbKey[6]] ^ sbKey[2]];
_sprBox[keyCtr++ * 2 + 0x201] = MDS3[(byte)Q1[(byte)Q1[Y3] ^ sbKey[7]] ^ sbKey[3]];
}
return wK;
}
private Int32[] ExpandKey(byte[] Key)
{
// expanded key size
int keySize = 4 * (_dfnRounds + 1);
// hkdf return array
int keyBytes = keySize * 4;
byte[] rawKey = new byte[keyBytes];
int saltSize = Key.Length - _ikmSize;
// salt must be divisible of hash blocksize
if (saltSize % _keyEngine.BlockSize != 0)
saltSize = saltSize - saltSize % _keyEngine.BlockSize;
// hkdf input
byte[] hkdfKey = new byte[_ikmSize];
byte[] hkdfSalt = new byte[saltSize];
// copy hkdf key and salt from user key
Buffer.BlockCopy(Key, 0, hkdfKey, 0, _ikmSize);
Buffer.BlockCopy(Key, _ikmSize, hkdfSalt, 0, saltSize);
// HKDF generator expands array using an SHA512 HMAC
using (HKDF gen = new HKDF(_keyEngine, false))
{
gen.Initialize(hkdfSalt, hkdfKey, _hkdfInfo);
gen.Generate(rawKey);
}
// initialize working key
Int32[] wK = new Int32[keySize];
// copy bytes to working key
Buffer.BlockCopy(rawKey, 0, wK, 0, keyBytes);
return wK;
}
private void HKDFTest(int Size, byte[] Salt, byte[] Key, byte[] Info, byte[] Output)
{
byte[] outBytes = new byte[Size];
using (HKDF gen = new HKDF(new SHA256()))
{
gen.Initialize(Salt, Key, Info);
gen.Generate(outBytes, 0, Size);
}
if (Compare.AreEqual(outBytes, Output) == false)
throw new Exception("HKDF: Values are not equal! Expected: " + HexConverter.ToString(Output) + " Received: " + HexConverter.ToString(outBytes));
using (HKDF gen = new HKDF(new SHA256HMAC()))
{
gen.Initialize(Salt, Key, Info);
gen.Generate(outBytes, 0, Size);
}
if (Compare.AreEqual(outBytes, Output) == false)
throw new Exception("HKDF: Values are not equal! Expected: " + HexConverter.ToString(Output) + " Received: " + HexConverter.ToString(outBytes));
}