Question

我正在尝试在P192r1的素数域上实现标量乘法。通过使用从java Scalar Multiplication

借来的代码，点加法工作正常

但是关于点加倍我从该链接再次使用Code的地方，它没有得到正确的结果。我试图找到错误，但我找不到它。有谁已经解决了这个错误。

 `public static ECPoint doublePoint(ECPoint r) {
        // TODO Auto-generated method stub

 BigInteger ONE = new BigInteger("1");;
 BigInteger TWO = new BigInteger("2");
 BigInteger p = new BigInteger("6277101735386680763835789423207666416083908700390324961279");

        BigInteger slope = (r.getAffineX().pow(2)).multiply(new BigInteger("3"));

        slope = slope.add(new BigInteger("3"));
        slope = slope.multiply((r.getAffineY().multiply(TWO)).modInverse(p));
        BigInteger Xout = slope.pow(2).subtract(r.getAffineX().multiply(new BigInteger("2"))).mod(p);
        BigInteger Yout = (r.getAffineY().negate()).add(slope.multiply(r.getAffineX().subtract(Xout))).mod(p);
        ECPoint out = new ECPoint(Xout, Yout);
        return out;
    }`

Answer 1

原始代码在此行中添加了3

slope = slope.add(new BigInteger("3"));

但它应该添加a，因此请用此行替换

slope = slope.add(a);

其中a是

static BigInteger a = new BigInteger("6277101735386680763835789423207666416083908700390324961276");

然后你会得到

Doubling is correct

运行main函数时。

Prime场上椭圆曲线的标量乘法

1 个答案: