short: add infinity check before multiplying

indutny · Sep 4, 2019 · 7ec66ff · 7ec66ff
1 parent ee7970b
commit 7ec66ff
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Showing 2 changed files with 10 additions and 2 deletions.
diff --git a/lib/elliptic/curve/short.js b/lib/elliptic/curve/short.js
@@ -421,8 +421,9 @@ Point.prototype.getY = function getY() {
 
 Point.prototype.mul = function mul(k) {
   k = new BN(k, 16);
-
-  if (this._hasDoubles(k))
+  if (this.isInfinity())
+    return this;
+  else if (this._hasDoubles(k))
     return this.curve._fixedNafMul(this, k);
   else if (this.curve.endo)
     return this.curve._endoWnafMulAdd([ this ], [ k ]);

diff --git a/test/curve-test.js b/test/curve-test.js
@@ -253,6 +253,13 @@ describe('Curve', function() {
     var neg2 = neg.neg(true);
     assert(p.eq(neg2));
   });
+
+  it('should correctly handle scalar multiplication of zero', function() {
+    var curve = elliptic.curves.secp256k1.curve;
+    var p1 = curve.g.mul('0');
+    var p2 = p1.mul('2');
+    assert(p1.eq(p2));
+  });
 });
 
 describe('Point codec', function () {