public static ASNLSignatureType Generate(List <byte[]> x, List <Cryptography.ECC.ECPoint> P1, List <Cryptography.ECC.ECPoint> P2, List <int> indices)
{
List <byte[]> s1 = new List <byte[]>();
ASNLSignatureType asnlSig = new ASNLSignatureType();
asnlSig.InitSField();
for (int i = 0; i < AMOUNT_SIZE; i++)
{
SchnorrSignatureType schnorrSig = SchnorrNonLinkable.Generate(x[i], P1[i], P2[i], indices[i]);
if (!SchnorrNonLinkable.Verify(P1[i], P2[i], schnorrSig))
{
throw new Exception("Schnorr Sign Error!");
}
asnlSig.L1.Add(schnorrSig.L1);
s1.Add(schnorrSig.s1);
asnlSig.s2.Add(schnorrSig.s2);
asnlSig.s = ScalarFunctions.Add(asnlSig.s, s1[i]);
}
return(asnlSig.Exports());
}
/// <summary>
/// Generate gives C, and mask such that \sumCi = C
/// c.f. http://eprint.iacr.org/2015/1098 section 5.1
/// and Ci is a commitment to either 0 or 2^i, i=0,...,63
/// thus this proves that "amount" is in [0, 2^64]
/// mask is a such that C = aG + bH, and b = amount
/// </summary>
/// <returns></returns>
public static RangeProveType Generate(Fixed8 amount)
{
Initialize();
byte[] mask = new byte[32];
ECPoint C = new ECPoint();
List <int> binaryAmount = amount.ToBinaryFormat();
List <byte[]> ai = new List <byte[]>();
List <ECPoint> CiH = new List <ECPoint>();
RangeProveType rangeProver = new RangeProveType();
for (int i = 0; i < ASNLRingSignature.AMOUNT_SIZE; i++)
{
byte[] ai_i = new byte[32];
ai.Add(ai_i);
if (binaryAmount[i] == 0)
{
rangeProver.rangeSig.Ci.Add(ECCurve.Secp256r1.G * ai_i);
}
else if (binaryAmount[i] == 1)
{
rangeProver.rangeSig.Ci.Add(ECCurve.Secp256r1.G * ai_i + H2[i]);
}
else
{
throw new Exception("Range Prove => Binary Format Error!");
}
CiH.Add(rangeProver.rangeSig.Ci[i] - H2[i]);
mask = ScalarFunctions.Add(mask, ai[i]);
if (i == 0)
{
C = rangeProver.rangeSig.Ci[i];
}
else
{
C = C + rangeProver.rangeSig.Ci[i];
}
}
rangeProver.C = C;
rangeProver.mask = mask;
rangeProver.rangeSig.AsnlSig = ASNLRingSignature.Generate(ai, rangeProver.rangeSig.Ci, CiH, binaryAmount);
if (!ASNLRingSignature.Verify(rangeProver.rangeSig.Ci, CiH, rangeProver.rangeSig.AsnlSig))
{
throw new Exception("Range prove error => ASNL verify error!");
}
return(rangeProver.Export());
}
public static EcdhTuple EcdhDecode(this EcdhTuple mask, byte[] recieverSK)
{
EcdhTuple unmask = mask;
byte[] sharedSec1 = Cryptography.Crypto.Default.Hash256(ScalarFunctions.MulWithPoint(mask.senderPK, recieverSK));
byte[] sharedSec2 = Cryptography.Crypto.Default.Hash256(sharedSec1);
unmask.mask = ScalarFunctions.Sub(mask.mask, sharedSec1);
unmask.amount = ScalarFunctions.Sub(mask.amount, sharedSec2);
return(unmask);
}
public static EcdhTuple EcdhEncode(this EcdhTuple unmask, ECPoint receiverPk)
{
EcdhTuple ret = new EcdhTuple();
byte[] esk = SchnorrNonLinkable.GenerateRandomScalar();
ret.senderPK = ECCurve.Secp256r1.G * esk;
byte[] sharedSec1 = Cryptography.Crypto.Default.Hash256(ScalarFunctions.MulWithPoint(receiverPk, esk));
byte[] sharedSec2 = Cryptography.Crypto.Default.Hash256(sharedSec1);
ret.mask = ScalarFunctions.Add(unmask.mask, sharedSec1);
ret.amount = ScalarFunctions.Add(unmask.amount, sharedSec2);
return(ret);
}
public static bool Verify(List <List <ECPoint> > PK, MLSAGSignatureType sig)
{
int rows = PK[0].Count;
int cols = PK.Count;
if (cols < 2)
{
throw new Exception("Error! What is c if cols = 1!");
}
int i = 0;
byte[] c_old = new byte[32];
Buffer.BlockCopy(sig.cc, 0, c_old, 0, sig.cc.Length);
List <ECPoint> Li = new List <ECPoint>();
List <byte[]> Ri = new List <byte[]>();
while (i < cols)
{
Li.Clear();
Ri.Clear();
for (int j = 0; j < rows; j++)
{
ECPoint L = ECCurve.Secp256r1.G * sig.ss[i][j] + PK[i][j] * c_old;
byte[] Hi = Crypto.Default.Hash256(PK[i][j].ToString().HexToBytes());
byte[] R = ScalarFunctions.Add(ScalarFunctions.Mul(sig.ss[i][j], Hi), ScalarFunctions.Mul(c_old, sig.II[j]));
Li.Add(L);
Ri.Add(R);
}
c_old = MakeHash(PK[i], Li, Ri);
i = i + 1;
}
return(sig.cc.ToHexString() == c_old.ToHexString());
}
public static SchnorrSignatureType Generate(byte[] x, Cryptography.ECC.ECPoint P1, Cryptography.ECC.ECPoint P2, int index)
{
byte[] a = GenerateRandomScalar();
if (index == 0)
{
Cryptography.ECC.ECPoint L1 = Cryptography.ECC.ECCurve.Secp256r1.G * a;
byte[] s2 = GenerateRandomScalar();
byte[] c2 = Crypto.Default.Hash256(L1.EncodePoint(true));
Cryptography.ECC.ECPoint L2 = Cryptography.ECC.ECCurve.Secp256r1.G * s2 + P2 * c2;
byte[] c1 = Crypto.Default.Hash256(L2.EncodePoint(true));
byte[] s1 = ScalarFunctions.MulSub(c1, x, a);
SchnorrSignatureType retSig = new SchnorrSignatureType(L1, s1, s2);
return(retSig);
}
else if (index == 1)
{
Cryptography.ECC.ECPoint L2 = Cryptography.ECC.ECCurve.Secp256r1.G * a;
byte[] s1 = GenerateRandomScalar();
byte[] c1 = Crypto.Default.Hash256(L2.EncodePoint(true));
Cryptography.ECC.ECPoint L1 = Cryptography.ECC.ECCurve.Secp256r1.G * s1 + P1 * c1;
byte[] c2 = Crypto.Default.Hash256(L1.EncodePoint(true));
byte[] s2 = ScalarFunctions.MulSub(c2, x, a);
SchnorrSignatureType retSig = new SchnorrSignatureType(L1, s1, s2);
return(retSig);
}
else
{
throw new Exception("SchnorrNonLinkable Index Overload Error!");
}
}
public static MLSAGSignatureType Generate(List <List <ECPoint> > PK, List <byte[]> X, int index)
{
MLSAGSignatureType sig = new MLSAGSignatureType();
int rows = PK[0].Count;
int cols = PK.Count;
#region Initialize
for (int j = 0; j < cols; j++)
{
sig.ss.Add(new List <byte[]>());
}
#endregion
if (cols < 2)
{
throw new Exception("Error! What is c if cols = 1!");
}
List <byte[]> alpha = new List <byte[]>();
List <ECPoint> aG = new List <ECPoint>();
List <byte[]> aHP = new List <byte[]>();
List <ECPoint> Li = new List <ECPoint>();
List <byte[]> Ri = new List <byte[]>();
for (int j = 0; j < rows; j++)
{
byte[] a = SchnorrNonLinkable.GenerateRandomScalar();
alpha.Add(a);
aG.Add(ECCurve.Secp256r1.G * a);
byte[] Hi = Crypto.Default.Hash256(PK[index][j].ToString().HexToBytes());
aHP.Add(ScalarFunctions.Mul(a, Hi));
sig.II.Add(ScalarFunctions.Mul(X[j], Hi));
}
byte[] c_old = MakeHash(PK[index], aG, aHP);
int i = (index + 1) % cols;
if (i == 0)
{
Buffer.BlockCopy(c_old, 0, sig.cc, 0, c_old.Length);
}
while (i != index)
{
for (int j = 0; j < rows; j++)
{
sig.ss[i].Add(SchnorrNonLinkable.GenerateRandomScalar());
}
byte[] c = new byte[32];
Li.Clear();
Ri.Clear();
for (int j = 0; j < rows; j++)
{
ECPoint L = ECCurve.Secp256r1.G * sig.ss[i][j] + PK[i][j] * c_old;
byte[] Hi = Crypto.Default.Hash256(PK[i][j].ToString().HexToBytes());
byte[] R = ScalarFunctions.Add(ScalarFunctions.Mul(sig.ss[i][j], Hi), ScalarFunctions.Mul(c_old, sig.II[j]));
Li.Add(L);
Ri.Add(R);
}
c_old = MakeHash(PK[i], Li, Ri);
i = (i + 1) % cols;
if (i == 0)
{
Buffer.BlockCopy(c_old, 0, sig.cc, 0, c_old.Length);
}
}
for (int j = 0; j < rows; j++)
{
sig.ss[index].Add(ScalarFunctions.MulSub(c_old, X[j], alpha[j]));
}
return(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));
}