diff --git a/lib/dart/pubspec.yaml b/lib/dart/pubspec.yaml
index 99d490c..7012f5d 100644
--- a/lib/dart/pubspec.yaml
+++ b/lib/dart/pubspec.yaml
@@ -26,6 +26,7 @@
   sdk: ">=1.12.0 <2.0.0"
 dependencies:
   crypto: "^0.9.0"
+  fixnum: "^0.10.2"
   http: "^0.11.3"
   logging: "^0.11.0"
 dev_dependencies: