internal static void secp256k1_musig_nonce_process_internal(
ECMultContext ecmult_ctx,
out bool fin_nonce_parity,
Span <byte> fin_nonce,
out Scalar b,
Span <GEJ> aggnoncej,
ReadOnlySpan <byte> agg_pk32,
ReadOnlySpan <byte> msg)
{
Span <byte> noncehash = stackalloc byte[32];
Span <GE> aggnonce = stackalloc GE[2];
aggnonce[0] = aggnoncej[0].ToGroupElement();
aggnonce[1] = aggnoncej[1].ToGroupElement();
secp256k1_musig_compute_noncehash(noncehash, aggnonce, agg_pk32, msg);
/* aggnonce = aggnonces[0] + b*aggnonces[1] */
b = new Scalar(noncehash);
var fin_nonce_ptj = ecmult_ctx.Mult(aggnoncej[1], b, null);
fin_nonce_ptj = fin_nonce_ptj.Add(aggnonce[0]);
var fin_nonce_pt = fin_nonce_ptj.ToGroupElement();
ECXOnlyPubKey.secp256k1_xonly_ge_serialize(fin_nonce, ref fin_nonce_pt);
fin_nonce_pt = fin_nonce_pt.NormalizeYVariable();
fin_nonce_parity = fin_nonce_pt.y.IsOdd;
}
internal static GE secp256k1_musig_process_nonces_internal(
ECMultContext ecmult_ctx,
Span <byte> noncehash,
Span <GEJ> summed_noncesj,
ReadOnlySpan <byte> combined_pk32,
ReadOnlySpan <byte> msg)
{
Scalar b;
GEJ combined_noncej;
Span <GE> summed_nonces = stackalloc GE[2];
summed_nonces[0] = summed_noncesj[0].ToGroupElement();
summed_nonces[1] = summed_noncesj[1].ToGroupElement();
secp256k1_musig_compute_noncehash(noncehash, summed_nonces, combined_pk32, msg);
/* combined_nonce = summed_nonces[0] + b*summed_nonces[1] */
b = new Scalar(noncehash);
combined_noncej = ecmult_ctx.Mult(summed_noncesj[1], b, null);
combined_noncej = combined_noncej.Add(summed_nonces[0]);
return(combined_noncej.ToGroupElement());
}