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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).

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package org.bouncycastle.math.ec;

import java.math.BigInteger;

public class ZSignedDigitR2LMultiplier extends AbstractECMultiplier
{
    /**
     * 'Zeroless' Signed Digit Right-to-Left.
     */
    protected ECPoint multiplyPositive(ECPoint p, BigInteger k)
    {
        ECPoint R0 = p.getCurve().getInfinity(), R1 = p;

        int n = k.bitLength();
        int s = k.getLowestSetBit();

        R1 = R1.timesPow2(s);

        int i = s;
        while (++i < n)
        {
            R0 = R0.add(k.testBit(i) ? R1 : R1.negate());
            R1 = R1.twice();
        }

        R0 = R0.add(R1);

        return R0;
    }
}