diff --git a/.travis.yml b/.travis.yml
index f900861..ef5fda5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,6 +8,7 @@ addons:
       - cmake
       - build-essential
       - ninja-build
+      - libssl-dev
 install:
   - pip install yotta
 script: