Examples with ECFieldElement com.github.zhenwei.core.math.ec.ECFieldElement used on opensource projects

Example 91 with ECFieldElement

use of com.github.zhenwei.core.math.ec.ECFieldElement in project LinLong-Java by zhenwei1108.

the class SecT409K1Point method twicePlus.

public ECPoint twicePlus(ECPoint b) {
    if (this.isInfinity()) {
        return b;
    }
    if (b.isInfinity()) {
        return twice();
    }
    ECCurve curve = this.getCurve();
    ECFieldElement X1 = this.x;
    if (X1.isZero()) {
        // A point with X == 0 is its own additive inverse
        return b;
    }
    // NOTE: twicePlus() only optimized for lambda-affine argument
    ECFieldElement X2 = b.getRawXCoord(), Z2 = b.getZCoord(0);
    if (X2.isZero() || !Z2.isOne()) {
        return twice().add(b);
    }
    ECFieldElement L1 = this.y, Z1 = this.zs[0];
    ECFieldElement L2 = b.getRawYCoord();
    ECFieldElement X1Sq = X1.square();
    ECFieldElement L1Sq = L1.square();
    ECFieldElement Z1Sq = Z1.square();
    ECFieldElement L1Z1 = L1.multiply(Z1);
    ECFieldElement T = L1Sq.add(L1Z1);
    ECFieldElement L2plus1 = L2.addOne();
    ECFieldElement A = L2plus1.multiply(Z1Sq).add(L1Sq).multiplyPlusProduct(T, X1Sq, Z1Sq);
    ECFieldElement X2Z1Sq = X2.multiply(Z1Sq);
    ECFieldElement B = X2Z1Sq.add(T).square();
    if (B.isZero()) {
        if (A.isZero()) {
            return b.twice();
        }
        return curve.getInfinity();
    }
    if (A.isZero()) {
        return new SecT409K1Point(curve, A, curve.getB());
    }
    ECFieldElement X3 = A.square().multiply(X2Z1Sq);
    ECFieldElement Z3 = A.multiply(B).multiply(Z1Sq);
    ECFieldElement L3 = A.add(B).square().multiplyPlusProduct(T, L2plus1, Z3);
    return new SecT409K1Point(curve, X3, L3, new ECFieldElement[] { Z3 });
}

Example 92 with ECFieldElement

use of com.github.zhenwei.core.math.ec.ECFieldElement in project LinLong-Java by zhenwei1108.

the class SecT409K1Point method getYCoord.

public ECFieldElement getYCoord() {
    ECFieldElement X = x, L = y;
    if (this.isInfinity() || X.isZero()) {
        return L;
    }
    // Y is actually Lambda (X + Y/X) here; convert to affine value on the fly
    ECFieldElement Y = L.add(X).multiply(X);
    ECFieldElement Z = zs[0];
    if (!Z.isOne()) {
        Y = Y.divide(Z);
    }
    return Y;
}

Example 93 with ECFieldElement

use of com.github.zhenwei.core.math.ec.ECFieldElement in project LinLong-Java by zhenwei1108.

the class SecT409K1Point method getCompressionYTilde.

protected boolean getCompressionYTilde() {
    ECFieldElement X = this.getRawXCoord();
    if (X.isZero()) {
        return false;
    }
    ECFieldElement Y = this.getRawYCoord();
    // Y is actually Lambda (X + Y/X) here
    return Y.testBitZero() != X.testBitZero();
}

Example 94 with ECFieldElement

use of com.github.zhenwei.core.math.ec.ECFieldElement in project LinLong-Java by zhenwei1108.

the class SecT409R1Point method getYCoord.

public ECFieldElement getYCoord() {
    ECFieldElement X = x, L = y;
    if (this.isInfinity() || X.isZero()) {
        return L;
    }
    // Y is actually Lambda (X + Y/X) here; convert to affine value on the fly
    ECFieldElement Y = L.add(X).multiply(X);
    ECFieldElement Z = zs[0];
    if (!Z.isOne()) {
        Y = Y.divide(Z);
    }
    return Y;
}

Example 95 with ECFieldElement

use of com.github.zhenwei.core.math.ec.ECFieldElement in project LinLong-Java by zhenwei1108.

the class SecT409R1Point method add.

public ECPoint add(ECPoint b) {
    if (this.isInfinity()) {
        return b;
    }
    if (b.isInfinity()) {
        return this;
    }
    ECCurve curve = this.getCurve();
    ECFieldElement X1 = this.x;
    ECFieldElement X2 = b.getRawXCoord();
    if (X1.isZero()) {
        if (X2.isZero()) {
            return curve.getInfinity();
        }
        return b.add(this);
    }
    ECFieldElement L1 = this.y, Z1 = this.zs[0];
    ECFieldElement L2 = b.getRawYCoord(), Z2 = b.getZCoord(0);
    boolean Z1IsOne = Z1.isOne();
    ECFieldElement U2 = X2, S2 = L2;
    if (!Z1IsOne) {
        U2 = U2.multiply(Z1);
        S2 = S2.multiply(Z1);
    }
    boolean Z2IsOne = Z2.isOne();
    ECFieldElement U1 = X1, S1 = L1;
    if (!Z2IsOne) {
        U1 = U1.multiply(Z2);
        S1 = S1.multiply(Z2);
    }
    ECFieldElement A = S1.add(S2);
    ECFieldElement B = U1.add(U2);
    if (B.isZero()) {
        if (A.isZero()) {
            return twice();
        }
        return curve.getInfinity();
    }
    ECFieldElement X3, L3, Z3;
    if (X2.isZero()) {
        // TODO This can probably be optimized quite a bit
        ECPoint p = this.normalize();
        X1 = p.getXCoord();
        ECFieldElement Y1 = p.getYCoord();
        ECFieldElement Y2 = L2;
        ECFieldElement L = Y1.add(Y2).divide(X1);
        X3 = L.square().add(L).add(X1).addOne();
        if (X3.isZero()) {
            return new SecT409R1Point(curve, X3, curve.getB().sqrt());
        }
        ECFieldElement Y3 = L.multiply(X1.add(X3)).add(X3).add(Y1);
        L3 = Y3.divide(X3).add(X3);
        Z3 = curve.fromBigInteger(ECConstants.ONE);
    } else {
        B = B.square();
        ECFieldElement AU1 = A.multiply(U1);
        ECFieldElement AU2 = A.multiply(U2);
        X3 = AU1.multiply(AU2);
        if (X3.isZero()) {
            return new SecT409R1Point(curve, X3, curve.getB().sqrt());
        }
        ECFieldElement ABZ2 = A.multiply(B);
        if (!Z2IsOne) {
            ABZ2 = ABZ2.multiply(Z2);
        }
        L3 = AU2.add(B).squarePlusProduct(ABZ2, L1.add(Z1));
        Z3 = ABZ2;
        if (!Z1IsOne) {
            Z3 = Z3.multiply(Z1);
        }
    }
    return new SecT409R1Point(curve, X3, L3, new ECFieldElement[] { Z3 });
}