public PubKey GetSharedPubkey(Key key)
{
#if HAS_SPAN
if (key == null)
{
throw new ArgumentNullException(nameof(key));
}
return(new PubKey(ECKey.GetSharedPubkey(key._ECKey), true));
#else
var pub = _ECKey.GetPublicKeyParameters();
var privKey = key._ECKey.PrivateKey;
if (!pub.Parameters.Equals(privKey.Parameters))
{
throw new InvalidOperationException("ECDH public key has wrong domain parameters");
}
ECPoint q = pub.Q.Multiply(privKey.D).Normalize();
if (q.IsInfinity)
{
throw new InvalidOperationException("Infinity is not a valid agreement value for ECDH");
}
var pubkey = ECKey.Secp256k1.Curve.CreatePoint(q.XCoord.ToBigInteger(), q.YCoord.ToBigInteger());
pubkey = pubkey.Normalize();
return(new ECKey(pubkey.GetEncoded(true), false).GetPubKey(true));
#endif
}