diff --git a/build/sjcl.js b/build/sjcl.js
index 8e2c9a2a..b2c436dc 100644
--- a/build/sjcl.js
+++ b/build/sjcl.js
@@ -4043,6 +4043,24 @@ sjcl.ecc.ecdsa.publicKey.prototype = {
   }
 };
 
+sjcl.ecc.ecdsa.secretKey.prototype.canonicalizeSignature = function(rs) {
+  var w = sjcl.bitArray,
+      R = this._curve.r,
+      l = R.bitLength();
+
+  var r = sjcl.bn.fromBits(w.bitSlice(rs,0,l)),
+      s = sjcl.bn.fromBits(w.bitSlice(rs,l,2*l));
+
+  // For a canonical signature we want the lower of two possible values for s
+  // 0 < s <= n/2
+  if (!R.copy().halveM().greaterEquals(s)) {
+    s = R.sub(s);
+  }
+
+  return w.concat(r.toBits(l), s.toBits(l));
+};
+
+
 sjcl.ecc.ecdsa.secretKey.prototype.signDER = function(hash, paranoia) {
   return this.encodeDER(this.sign(hash, paranoia));
 };