private byte[] GetHash(byte[] message)
{
var h = new byte[BlockSize];
_n = new byte[BlockSize];
_sigma = new byte[BlockSize];
Array.Copy(_iv, h, BlockSize);
byte[] n0 = new byte[BlockSize];
IEnumerable <IEnumerable <byte> > blocks = message.Batch(BlockSize).ToArray();
blocks.Where(block => block.Count() >= BlockSize).Reverse().ForEach(block =>
{
h = G_n(_n, h, block);
_n = _n.AddModulo64(BitConverter.GetBytes((long)64).Reverse().ToArray());
_sigma = _sigma.AddModulo64(block.ToArray());
});
var lastBlockSize = blocks.Last().Count();
byte[] pad = MoreEnumerable
.Append(new byte[lastBlockSize < BlockSize ? BlockSize - 1 - lastBlockSize : BlockSize - 1], (byte)1).ToArray();
byte[] m = pad
.Concat(blocks.Where(block => block.Count() < BlockSize).DefaultIfEmpty(new byte[0]).First()).ToArray();
h = G_n(_n, h, m);
var msgLen = BitConverter.GetBytes((long)(message.Length * 8)).Reverse();
_n = _n.AddModulo64(msgLen.ToArray());
_sigma = _sigma.AddModulo64(m);
h = G_n(n0, h, _n);
h = G_n(n0, h, _sigma);
return(h);
}