diff --git a/src/secp256k1/.travis.yml b/src/secp256k1/.travis.yml
--- a/src/secp256k1/.travis.yml
+++ b/src/secp256k1/.travis.yml
@@ -3,13 +3,11 @@
 dist: xenial
 addons:
   apt:
-    sources:
-      - sourceline: 'deb https://apt.kitware.com/ubuntu/ xenial main'
-        key_url: 'https://apt.kitware.com/keys/kitware-archive-latest.asc'
     packages:
-      - cmake
       - libgmp-dev
       - ninja-build
+install:
+  - ./travis/install_cmake.sh
 compiler:
   - clang
   - gcc
@@ -59,48 +57,36 @@
       env: HOST=i686-linux-gnu ENDOMORPHISM=yes
       addons:
         apt:
-          sources:
-            - sourceline: 'deb https://apt.kitware.com/ubuntu/ xenial main'
-              key_url: 'https://apt.kitware.com/keys/kitware-archive-latest.asc'
           packages:
-            - cmake
             - gcc-multilib
             - libgmp-dev:i386
             - ninja-build
+      install: ./travis/install_cmake.sh
     - compiler: clang
       env: HOST=i686-linux-gnu BIGNUM=no
       addons:
         apt:
-          sources:
-            - sourceline: 'deb https://apt.kitware.com/ubuntu/ xenial main'
-              key_url: 'https://apt.kitware.com/keys/kitware-archive-latest.asc'
           packages:
-            - cmake
             - gcc-multilib
             - ninja-build
+      install: ./travis/install_cmake.sh
     - compiler: gcc
       env: HOST=i686-linux-gnu ENDOMORPHISM=yes BIGNUM=no
       addons:
         apt:
-          sources:
-            - sourceline: 'deb https://apt.kitware.com/ubuntu/ xenial main'
-              key_url: 'https://apt.kitware.com/keys/kitware-archive-latest.asc'
           packages:
-            - cmake
             - gcc-multilib
             - ninja-build
+      install: ./travis/install_cmake.sh
     - compiler: gcc
       env: HOST=i686-linux-gnu
       addons:
         apt:
-          sources:
-            - sourceline: 'deb https://apt.kitware.com/ubuntu/ xenial main'
-              key_url: 'https://apt.kitware.com/keys/kitware-archive-latest.asc'
           packages:
-            - cmake
             - gcc-multilib
             - libgmp-dev:i386
             - ninja-build
+      install: ./travis/install_cmake.sh
 script:
  - ./travis/build_autotools.sh
  - ./travis/build_cmake.sh
diff --git a/src/secp256k1/travis/install_cmake.sh b/src/secp256k1/travis/install_cmake.sh
new file mode 100755
--- /dev/null
+++ b/src/secp256k1/travis/install_cmake.sh
@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+export LC_ALL=C
+
+set -euxo pipefail
+
+# Fetch Kitware signing key
+wget -O - https://apt.kitware.com/keys/kitware-archive-latest.asc 2>/dev/null | sudo apt-key add -
+	
+# Add the Kitware PPA
+sudo apt-add-repository 'deb https://apt.kitware.com/ubuntu/ xenial main'
+sudo apt-get update
+
+# Install cmake
+sudo apt-get -y install cmake