/// <summary>
/// Builds tree from pub and also the public key as a BitString
/// </summary>
/// <param name="pub">A bunch of last 32 bytes of public keys</param>
/// <returns>LMS public key</returns>
private BitString GenerateLmsPublicKey(byte[] pub)
{
var tree = LmsDllLoader.BuildTreeWithPub(_h, _m, _I.ToBytes(), pub, _lmots.GetP(), _lmots.GetN(), _lmots.GetW());
_tree = new LmsTree(_h, _m, tree);
var publicKey = _typecode.ConcatenateBits(_lmotsTypecode)
.ConcatenateBits(_I)
.ConcatenateBits(_tree.GetRoot());
return(publicKey);
}
public BitString GenerateLmsSignature(BitString msg, LmsPrivateKey privateKey)
{
// 0. Use pub to generate tree if it is not null
if (privateKey.Pub != null)
{
var tree = LmsDllLoader.BuildTreeWithPub(_h, _m, _I.ToBytes(), privateKey.Pub, _lmots.GetP(), _lmots.GetN(), _lmots.GetW());
_tree = new LmsTree(_h, _m, tree);
}
// 1. Generate ots with next available leaf (in private key)
var q = privateKey.Q;
if (q * ((_lmots.GetN() * _lmots.GetP()) + 24) >= privateKey.OTS_PRIV.Length)
{
return(null);
}
var lmots_signature = _lmots.GenerateLmotsSignature(msg, new BitString(privateKey.GetLmotsPrivateKeyQ(q)), SEED);
// 2. Increment q in private key to ensure no reusablility of key
// privateKey.UpdateQ();
// currently done in hss
// 3. Determine path[]
var path = new BitString("");
int currentIndex = (1 << _h) + q;
for (int i = 0; i < _h; i++)
{
path = path.ConcatenateBits(_tree.GetSibling(currentIndex));
currentIndex /= 2;
}
// 4. u32str(q) || lmots_signature || u32str(type) || path[0] || path[1] || path[2] || ... || path[h - 1]
return(new BitString(q, 32)
.ConcatenateBits(lmots_signature)
.ConcatenateBits(_typecode)
.ConcatenateBits(path));
}
