diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/math/ec/ReferenceMultiplier.java')
-rw-r--r-- | core/src/main/java/org/bouncycastle/math/ec/ReferenceMultiplier.java | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/core/src/main/java/org/bouncycastle/math/ec/ReferenceMultiplier.java b/core/src/main/java/org/bouncycastle/math/ec/ReferenceMultiplier.java new file mode 100644 index 00000000..c1dd5483 --- /dev/null +++ b/core/src/main/java/org/bouncycastle/math/ec/ReferenceMultiplier.java @@ -0,0 +1,30 @@ +package org.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 org.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; + } +} |