nl.open.jwtdependency.org.bouncycastle.math.ec.NafR2LMultiplier Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of java-jwt-nodependencies Show documentation

This is a drop in replacement for the auth0 java-jwt library (see https://github.com/auth0/java-jwt). This jar makes sure there are no external dependencies (e.g. fasterXml, Apacha Commons) needed. This is useful when deploying to an application server (e.g. tomcat with Alfreso or Pega).

The newest version!

package org.bouncycastle.math.ec;

import java.math.BigInteger;

/**
 * Class implementing the NAF (Non-Adjacent Form) multiplication algorithm (right-to-left).
 */
public class NafR2LMultiplier extends AbstractECMultiplier
{
    protected ECPoint multiplyPositive(ECPoint p, BigInteger k)
    {
        int[] naf = WNafUtil.generateCompactNaf(k);

        ECPoint R0 = p.getCurve().getInfinity(), R1 = p;

        int zeroes = 0;
        for (int i = 0; i < naf.length; ++i)
        {
            int ni = naf[i];
            int digit = ni >> 16;
            zeroes += ni & 0xFFFF;

            R1 = R1.timesPow2(zeroes);
            R0 = R0.add(digit < 0 ? R1.negate() : R1);

            zeroes = 1;
        }

        return R0;
    }
}