public byte[] Hash(byte[] clearBytes)
{
using (var hmac = new HMACSHA512(_key))
{
hmac.Initialize();
byte[] hashBytes = hmac.ComputeHash(clearBytes);
return hashBytes;
}
}
// This function is defined as follow :
// Func (S, i) = HMAC(S || i) | HMAC2(S || i) | ... | HMAC(iterations) (S || i)
// where i is the block number.
private byte[] Func()
{
byte[] INT_block = Int(m_block);
m_HMACSHA512.TransformBlock(m_salt, 0, m_salt.Length, m_salt, 0);
m_HMACSHA512.TransformFinalBlock(INT_block, 0, INT_block.Length);
byte[] temp = m_HMACSHA512.Hash;
m_HMACSHA512.Initialize();
byte[] ret = temp;
for (int i = 2; i <= m_iterations; i++)
{
temp = m_HMACSHA512.ComputeHash(temp);
for (int j = 0; j < BlockSize; j++)
{
ret[j] ^= temp[j];
}
}
// increment the block count.
m_block++;
return(ret);
}
/// <summary>
/// NetAESEncryption constructor
/// </summary>
public NetAESEncryption(string key, int bitsize)
{
if (!m_keysizes.Contains(bitsize))
throw new NetException(string.Format("Not a valid key size. (Valid values are: {0})", NetUtility.MakeCommaDelimitedList(m_keysizes)));
byte[] entropy = Encoding.UTF32.GetBytes(key);
// I know hardcoding salts is bad, but in this case I think it is acceptable.
HMACSHA512 hmacsha512 = new HMACSHA512(Convert.FromBase64String("i88NEiez3c50bHqr3YGasDc4p8jRrxJAaiRiqixpvp4XNAStP5YNoC2fXnWkURtkha6M8yY901Gj07IRVIRyGL=="));
hmacsha512.Initialize();
for (int i = 0; i < 1000; i++)
{
entropy = hmacsha512.ComputeHash(entropy);
}
int keylen = bitsize / 8;
m_key = new byte[keylen];
Buffer.BlockCopy(entropy, 0, m_key, 0, keylen);
m_iv = new byte[m_blocksizes[0] / 8];
Buffer.BlockCopy(entropy, entropy.Length - m_iv.Length - 1, m_iv, 0, m_iv.Length);
m_bitSize = bitsize;
}
