diff --git a/lib/bcoin/hd.js b/lib/bcoin/hd.js
index eb92fdd6..996e518e 100644
--- a/lib/bcoin/hd.js
+++ b/lib/bcoin/hd.js
@@ -326,16 +326,7 @@ HDPriv.prototype.derive = function(index, hard) {
   var leftPart = new bn(hash.slice(0, 32));
   var chainCode = hash.slice(32, 64);
 
-  // XXX This causes a call stack overflow with bn.js@4.0.5 and elliptic@3.0.3
-  // Example: new bn(0).mod(ec.curve.n)
-  //var privateKey = leftPart.add(new bn(this.privateKey)).mod(ec.curve.n).toArray();
-
-  // Use this as a workaround:
-  var n = new bn(
-    'fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141',
-    'hex'
-  );
-  var privateKey = leftPart.add(new bn(this.privateKey)).mod(n).toArray();
+  var privateKey = leftPart.add(new bn(this.privateKey)).mod(ec.curve.n).toArray();
 
   return new HDPriv({
     // version: this.version,
diff --git a/package.json b/package.json
index 96b9811f..4e256420 100644
--- a/package.json
+++ b/package.json
@@ -23,7 +23,7 @@
   "dependencies": {
     "async": "^0.8.0",
     "bn.js": "^4.5.0",
-    "elliptic": "^3.0.3",
+    "elliptic": "^6.0.2",
     "hash.js": "^1.0.3",
     "inherits": "^2.0.1"
   },