diff --git a/package.json b/package.json
index 495e486..6633688 100644
--- a/package.json
+++ b/package.json
@@ -46,7 +46,7 @@
     "compile": "./node_modules/.bin/browserify ./src/index.js -s Bitcoin | ./node_modules/.bin/uglifyjs > bitcoinjs-min.js"
   },
   "dependencies": {
-    "bigi": "1.0.0",
+    "bigi": "1.1.0",
     "crypto-js": "3.1.2-3",
     "secure-random": "0.2.1"
   }
diff --git a/src/ecdsa.js b/src/ecdsa.js
index 1536918..7d73a6d 100644
--- a/src/ecdsa.js
+++ b/src/ecdsa.js
@@ -88,8 +88,8 @@ function verifyRaw(ecparams, e, r, s, Q) {
   * Takes two BigIntegers representing r and s and returns a byte array.
   */
 function serializeSig(r, s) {
-  var rBa = r.toByteArraySigned()
-  var sBa = s.toByteArraySigned()
+  var rBa = r.toDERInteger()
+  var sBa = s.toDERInteger()
 
   var sequence = []
   sequence.push(0x02); // INTEGER
@@ -130,8 +130,8 @@ function parseSig(buffer) {
   var sB = buffer.slice(2 + offset)
 
   return {
-    r: BigInteger.fromByteArraySigned(rB),
-    s: BigInteger.fromByteArraySigned(sB)
+    r: BigInteger.fromDERInteger(rB),
+    s: BigInteger.fromDERInteger(sB)
   }
 }