diff --git a/crypto/src/math/ec/ECCurve.cs b/crypto/src/math/ec/ECCurve.cs
index eaa3e0c3d..339d37f7c 100644
--- a/crypto/src/math/ec/ECCurve.cs
+++ b/crypto/src/math/ec/ECCurve.cs
@@ -221,26 +221,56 @@ namespace Org.BouncyCastle.Math.EC
*/
public virtual void NormalizeAll(ECPoint[] points)
{
- CheckPoints(points);
+ NormalizeAll(points, 0, points.Length, null);
+ }
+
+ /**
+ * Normalization ensures that any projective coordinate is 1, and therefore that the x, y
+ * coordinates reflect those of the equivalent point in an affine coordinate system. Where more
+ * than one point is to be normalized, this method will generally be more efficient than
+ * normalizing each point separately. An (optional) z-scaling factor can be applied; effectively
+ * each z coordinate is scaled by this value prior to normalization (but only one
+ * actual multiplication is needed).
+ *
+ * @param points
+ * An array of points that will be updated in place with their normalized versions,
+ * where necessary
+ * @param off
+ * The start of the range of points to normalize
+ * @param len
+ * The length of the range of points to normalize
+ * @param iso
+ * The (optional) z-scaling factor - can be null
+ */
+ public virtual void NormalizeAll(ECPoint[] points, int off, int len, ECFieldElement iso)
+ {
+ CheckPoints(points, off, len);
- if (this.CoordinateSystem == ECCurve.COORD_AFFINE)
+ switch (this.CoordinateSystem)
{
- return;
+ case ECCurve.COORD_AFFINE:
+ case ECCurve.COORD_LAMBDA_AFFINE:
+ {
+ if (iso != null)
+ throw new ArgumentException("not valid for affine coordinates", "iso");
+
+ return;
+ }
}
/*
* Figure out which of the points actually need to be normalized
*/
- ECFieldElement[] zs = new ECFieldElement[points.Length];
- int[] indices = new int[points.Length];
+ ECFieldElement[] zs = new ECFieldElement[len];
+ int[] indices = new int[len];
int count = 0;
- for (int i = 0; i < points.Length; ++i)
+ for (int i = 0; i < len; ++i)
{
- ECPoint p = points[i];
- if (null != p && !p.IsNormalized())
+ ECPoint p = points[off + i];
+ if (null != p && (iso != null || !p.IsNormalized()))
{
zs[count] = p.GetZCoord(0);
- indices[count++] = i;
+ indices[count++] = off + i;
}
}
@@ -249,7 +279,7 @@ namespace Org.BouncyCastle.Math.EC
return;
}
- ECAlgorithms.MontgomeryTrick(zs, 0, count);
+ ECAlgorithms.MontgomeryTrick(zs, 0, count, iso);
for (int j = 0; j < count; ++j)
{
@@ -298,12 +328,19 @@ namespace Org.BouncyCastle.Math.EC
protected virtual void CheckPoints(ECPoint[] points)
{
+ CheckPoints(points, 0, points.Length);
+ }
+
+ protected virtual void CheckPoints(ECPoint[] points, int off, int len)
+ {
if (points == null)
throw new ArgumentNullException("points");
+ if (off < 0 || len < 0 || (off > (points.Length - len)))
+ throw new ArgumentException("invalid range specified", "points");
- for (int i = 0; i < points.Length; ++i)
+ for (int i = 0; i < len; ++i)
{
- ECPoint point = points[i];
+ ECPoint point = points[off + i];
if (null != point && this != point.Curve)
throw new ArgumentException("entries must be null or on this curve", "points");
}
|
