GetLucas() public static method

public static GetLucas ( sbyte mu, int k, bool doV ) : BigInteger[]
mu sbyte
k int
doV bool
return BigInteger[]
Exemplo n.º 1
0
        public static BigInteger[] GetSi(AbstractF2mCurve curve)
        {
            if (!curve.IsKoblitz)
            {
                throw new ArgumentException("si is defined for Koblitz curves only");
            }
            int   fieldSize         = curve.FieldSize;
            int   intValue          = curve.A.ToBigInteger().IntValue;
            sbyte mu                = Tnaf.GetMu(intValue);
            int   shiftsForCofactor = Tnaf.GetShiftsForCofactor(curve.Cofactor);
            int   k = fieldSize + 3 - intValue;

            BigInteger[] lucas = Tnaf.GetLucas(mu, k, false);
            if (mu == 1)
            {
                lucas[0] = lucas[0].Negate();
                lucas[1] = lucas[1].Negate();
            }
            BigInteger bigInteger  = BigInteger.One.Add(lucas[1]).ShiftRight(shiftsForCofactor);
            BigInteger bigInteger2 = BigInteger.One.Add(lucas[0]).ShiftRight(shiftsForCofactor).Negate();

            return(new BigInteger[]
            {
                bigInteger,
                bigInteger2
            });
        }
Exemplo n.º 2
0
 public static BigInteger GetTw(sbyte mu, int w)
 {
     if (w != 4)
     {
         BigInteger[] lucas = Tnaf.GetLucas(mu, w, false);
         BigInteger   m     = BigInteger.Zero.SetBit(w);
         BigInteger   val   = lucas[1].ModInverse(m);
         return(BigInteger.Two.Multiply(lucas[0]).Multiply(val).Mod(m));
     }
     if (mu == 1)
     {
         return(BigInteger.ValueOf(6L));
     }
     return(BigInteger.ValueOf(10L));
 }
Exemplo n.º 3
0
        public static BigInteger[] GetSi(int fieldSize, int curveA, BigInteger cofactor)
        {
            sbyte mu = Tnaf.GetMu(curveA);
            int   shiftsForCofactor = Tnaf.GetShiftsForCofactor(cofactor);
            int   k = fieldSize + 3 - curveA;

            BigInteger[] lucas = Tnaf.GetLucas(mu, k, false);
            if (mu == 1)
            {
                lucas[0] = lucas[0].Negate();
                lucas[1] = lucas[1].Negate();
            }
            BigInteger bigInteger  = BigInteger.One.Add(lucas[1]).ShiftRight(shiftsForCofactor);
            BigInteger bigInteger2 = BigInteger.One.Add(lucas[0]).ShiftRight(shiftsForCofactor).Negate();

            return(new BigInteger[]
            {
                bigInteger,
                bigInteger2
            });
        }
Exemplo n.º 4
0
        public static ZTauElement PartModReduction(BigInteger k, int m, sbyte a, BigInteger[] s, sbyte mu, sbyte c)
        {
            BigInteger bigInteger;

            if (mu == 1)
            {
                bigInteger = s[0].Add(s[1]);
            }
            else
            {
                bigInteger = s[0].Subtract(s[1]);
            }
            BigInteger[]     lucas       = Tnaf.GetLucas(mu, m, true);
            BigInteger       vm          = lucas[1];
            SimpleBigDecimal lambda      = Tnaf.ApproximateDivisionByN(k, s[0], vm, a, m, (int)c);
            SimpleBigDecimal lambda2     = Tnaf.ApproximateDivisionByN(k, s[1], vm, a, m, (int)c);
            ZTauElement      zTauElement = Tnaf.Round(lambda, lambda2, mu);
            BigInteger       u           = k.Subtract(bigInteger.Multiply(zTauElement.u)).Subtract(BigInteger.ValueOf(2L).Multiply(s[1]).Multiply(zTauElement.v));
            BigInteger       v           = s[1].Multiply(zTauElement.u).Subtract(s[0].Multiply(zTauElement.v));

            return(new ZTauElement(u, v));
        }