package com.google.bitcoin.bouncycastle.math.ec; import java.math.BigInteger; class ReferenceMultiplier implements ECMultiplier { /** * Simple shift-and-add multiplication. Serves as reference implementation * to verify (possibly faster) implementations in * {@link com.google.bitcoin.bouncycastle.math.ec.ECPoint ECPoint}. * * @param p The point to multiply. * @param k The factor by which to multiply. * @return The result of the point multiplication <code>k * p</code>. */ public ECPoint multiply(ECPoint p, BigInteger k, PreCompInfo preCompInfo) { ECPoint q = p.getCurve().getInfinity(); int t = k.bitLength(); for (int i = 0; i < t; i++) { if (k.testBit(i)) { q = q.add(p); } p = p.twice(); } return q; } }