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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 abstract class AbstractECMultiplier implements ECMultiplier
{
    public ECPoint multiply(ECPoint p, BigInteger k)
    {
        int sign = k.signum();
        if (sign == 0 || p.isInfinity())
        {
            return p.getCurve().getInfinity();
        }

        ECPoint positive = multiplyPositive(p, k.abs());
        ECPoint result = sign > 0 ? positive : positive.negate();

        /*
         * Although the various multipliers ought not to produce invalid output under normal
         * circumstances, a final check here is advised to guard against fault attacks.
         */
        return ECAlgorithms.validatePoint(result);
    }

    protected abstract ECPoint multiplyPositive(ECPoint p, BigInteger k);
}