public static bool VerRctMG(MLSAGSignatureType sig, List <List <CTKey> > pubs, List <CTKey> outPK, Fixed8 vPub)
{
int rows = pubs[0].Count;
int cols = pubs.Count;
List <List <ECPoint> > M = new List <List <ECPoint> >();
for (int i = 0; i < cols; i++)
{
List <ECPoint> M_i = new List <ECPoint>();
ECPoint M_row = new ECPoint();
for (int j = 0; j < rows; j++)
{
M_i.Add(pubs[i][j].dest);
M_row = M_row + pubs[i][j].mask;
}
M_i.Add(M_row);
M.Add(M_i);
}
for (int i = 0; i < cols; i++)
{
for (int j = 0; j < outPK.Count; j++)
{
M[i][rows] = M[i][rows] - outPK[j].mask;
}
if (vPub > Fixed8.Zero)
{
byte[] b_vPub = vPub.ToBinaryFormat().ToBinary();
M[i][rows] = M[i][rows] - RangeSignature.H * b_vPub;
}
else if (vPub < Fixed8.Zero)
{
byte[] b_vPub = (-vPub).ToBinaryFormat().ToBinary();
M[i][rows] = M[i][rows] + RangeSignature.H * b_vPub;
}
}
return(MLSAGSignature.Verify(M, sig));
}
/// <summary>
/// Tag-Linkable Ring-CT with Multiple Inputs and One-time Keys
/// c.f. http://eprint.iacr.org/2015/1098 section 4. definition 10.
/// This does the MG sig on the "dest" part of the given key matrix, and
/// the last row is the sum of input commitments from that column - sum output commitments
/// this shows that sum inputs = sum outputs
/// </summary>
/// <param name="pubs">Public keys using from Ring CT -> {P(i,j), C(i,j)}</param>
/// <param name="inSK">Private keys for public keys</param>
/// <param name="outSK">C_out sk</param>
/// <param name="outPK">C_out PK</param>
/// <param name="index">Signer's index</param>
/// <returns></returns>
public static MLSAGSignatureType ProveRctMG(List <List <CTKey> > pubs, List <CTCommitment> inSK, List <CTCommitment> outSK, List <CTKey> outPK, Fixed8 vPub, int index)
{
int rows = pubs[0].Count;
int cols = pubs.Count;
List <byte[]> sk = new List <byte[]>();
List <byte[]> tmp = new List <byte[]>();
for (int i = 0; i < rows + 1; i++)
{
byte[] sk_i = new byte[32];
sk.Add(sk_i);
}
List <List <ECPoint> > M = new List <List <ECPoint> >();
for (int i = 0; i < cols; i++)
{
List <ECPoint> M_i = new List <ECPoint>();
ECPoint M_row = new ECPoint();
for (int j = 0; j < rows; j++)
{
M_i.Add(pubs[i][j].dest);
M_row = M_row + pubs[i][j].mask;
}
M_i.Add(M_row);
M.Add(M_i);
}
for (int i = 0; i < cols; i++)
{
for (int j = 0; j < outPK.Count; j++)
{
M[i][rows] = M[i][rows] - outPK[j].mask;
}
if (vPub > Fixed8.Zero)
{
byte[] b_vPub = vPub.ToBinaryFormat().ToBinary();
M[i][rows] = M[i][rows] - RangeSignature.H * b_vPub;
}
else if (vPub < Fixed8.Zero)
{
byte[] b_vPub = (-vPub).ToBinaryFormat().ToBinary();
M[i][rows] = M[i][rows] + RangeSignature.H * b_vPub;
}
}
byte[] sk_row = inSK[0].mask;
for (int i = 0; i < rows; i++)
{
sk[i] = inSK[i].dest;
if (i > 0)
{
sk_row = ScalarFunctions.Add(sk_row, inSK[i].mask);
}
}
sk[rows] = sk_row;
for (int i = 0; i < outPK.Count; i++)
{
sk[rows] = ScalarFunctions.Sub(sk[rows], outSK[i].mask);
}
return(MLSAGSignature.Generate(M, sk, index));
}
