/// <summary>
/// Generates a Hss Key Pair asynchronously. Safe to call from an Orleans grain.
/// </summary>
/// <returns>Valid HssKeyPair</returns>
public async Task <HssKeyPair> GenerateHssKeyPairAsync()
{
LmsPrivateKey[] priv = new LmsPrivateKey[_lms.Length];
BitString[] pub = new BitString[_lms.Length];
BitString[] sig = new BitString[_lms.Length - 1];
// Generate Key Pairs
await GenerateHssKeyPairHelperAsync(priv, pub);
// Generate sig list
for (int i = 1; i < _lms.Length; i++)
{
sig[i - 1] = _lms[i - 1].GenerateLmsSignature(pub[i], priv[i - 1]);
}
// Return u32str(L) || pub[0] as the public key and the priv[], pub[], and sig[] arrays as the private key
var publicKey = new BitString(_lms.Length, 32).ConcatenateBits(pub[0]);
var privateKey = new HssPrivateKey(priv, pub, sig);
return(new HssKeyPair(privateKey, 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));
}
