bool LRSPublicKey::Verify(const QByteArray &data, const LRSSignature &sig) const
{
if(!sig.IsValid()) {
qDebug() << "Invalid signature";
return false;
}
if(sig.SignatureCount() != GetKeys().count()) {
qDebug() << "Incorrect amount of keys used to generate signature.";
return false;
}
CppHash hash;
hash.Update(GetGroupGenerator().GetByteArray());
hash.Update(sig.GetTag().GetByteArray());
hash.Update(data);
QByteArray precompute = hash.ComputeHash();
Integer tcommit = sig.GetCommit1();
QVector<Integer> keys = GetKeys();
for(int idx = 0; idx < keys.count(); idx++) {
Integer z_p = (GetGenerator().Pow(sig.GetSignature(idx), GetModulus()) *
_keys[idx].Pow(tcommit, GetModulus())) % GetModulus();
Integer z_pp = (GetGroupGenerator().Pow(sig.GetSignature(idx), GetModulus()) *
sig.GetTag().Pow(tcommit, GetModulus())) % GetModulus();
hash.Update(precompute);
hash.Update(z_p.GetByteArray());
hash.Update(z_pp.GetByteArray());
tcommit = Integer(hash.ComputeHash()) % GetSubgroup();
}
return tcommit == sig.GetCommit1();
}
/**
* Called to generate the shufflers group
*/
virtual void GenerateShufflerGroup()
{
SetShufflers(GetGroupGenerator()->NextGroup());
}