srs

public class SecretKey {
    BigInteger x;

    public BigInteger getX() {
        return x;
    }

    public void setX(BigInteger x) {
        this.x = x;
    }
}

public class PublicKey {
    ECPoint G;
    ECPoint Y;
    BigInteger q;

    public ECPoint getG() {
        return G;
    }
    public void setG(ECPoint g) {
        G = g;
    }
    public ECPoint getY() {
        return Y;
    }
    public void setY(ECPoint y) {
        Y = y;
    }
    public BigInteger getQ() {
        return q;
    }
    public void setQ(BigInteger q) {
        this.q = q;
    }
}

public class RingSchnorr {

    public static void keyGen(String curveName, User u) {
        ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec(curveName);

        u.getPk().setG(ecSpec.getG());
        u.getPk().setQ(ecSpec.getN());

        u.getSk().setX(BigIntegers.createRandomInRange(BigInteger.ONE, u.getPk().getQ().subtract(BigInteger.ONE),
                new SecureRandom()));
        u.getPk().setY(u.getPk().getG().multiply(u.getSk().getX()).normalize());
    }

    public static BigInteger hashVal(String m, ECPoint R){
        byte[] xArray = R.getXCoord().getEncoded();
        byte[] yArray = R.getYCoord().getEncoded();

        String xBinary;
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < xArray.length; i++) {
            sb.append(String.format("%8s", Integer.toBinaryString(xArray[i] & 0xFF)).replace(' ', '0'));
        }
        xBinary = sb.toString();

        sb = new StringBuilder();
        String yBinary;
        for (int i = 0; i < yArray.length; i++) {
            sb.append(String.format("%8s", Integer.toBinaryString(yArray[i] & 0xFF)).replace(' ', '0'));
        }
        yBinary = sb.toString();

        int hash = (xBinary + yBinary + m).hashCode();
        BigInteger h = BigInteger.valueOf(hash);
        return h;

    }

    public static void main(String[] args) {
        User u1 = new User();
        User u2 = new User();
        User u3 = new User();

        keyGen("prime192v1", u1);
        keyGen("prime192v1", u2);
        keyGen("prime192v1", u3);
        ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("prime192v1");

        BigInteger a2 = BigIntegers.createRandomInRange(BigInteger.ONE,
                u2.getPk().getQ().subtract(BigInteger.ONE), new SecureRandom());
        ECPoint R2 = u2.getPk().getG().multiply((a2)).normalize();

        BigInteger a3 = BigIntegers.createRandomInRange(BigInteger.ONE,
                u3.getPk().getQ().subtract(BigInteger.ONE), new SecureRandom());
        ECPoint R3 = u3.getPk().getG().multiply((a3)).normalize();

        BigInteger a = (BigIntegers.createRandomInRange(BigInteger.ONE, u2.getPk().getQ().subtract(BigInteger.ONE),
                new SecureRandom()));

        BigInteger modulus = ecSpec.getCurve().getField().getCharacteristic();
        BigInteger HR2 = hashVal("m", R2);
        BigInteger invHR2 = HR2.modInverse(modulus);
        BigInteger HR3 = hashVal("m", R3);
        BigInteger invHR3 = HR3.modInverse(modulus);

        ECPoint Rs = ecSpec.getG().multiply(a).add(u2.getPk().getY().multiply(invHR2)).add(u3.getPk().getY().multiply(invHR3)).normalize();

        BigInteger HR1 = hashVal("m", Rs);
        BigInteger tmp = u1.getSk().getX().multiply(HR1);
        BigInteger sigma = a.add(a2).add(a3).add(tmp).mod(ecSpec.getN());

        ECPoint y1 = u1.getPk().getY().multiply(HR1).normalize();
        ECPoint y2 = u2.getPk().getY().multiply(HR2).normalize();
        ECPoint y3 = u3.getPk().getY().multiply(HR3).normalize();

        ECPoint check = Rs.add(R2).add(R3).add(y1).add(y2).add(y3).normalize();
        ECPoint check2 = ecSpec.getG().multiply(sigma).normalize();

        System.out.println(check);
        System.out.println(check2);

        System.out.println("end");
    }

}