diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b279816..fd4cbeb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,6 +9,9 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      id-token: write
     strategy:
       fail-fast: false
       matrix:
@@ -28,7 +31,7 @@ jobs:
             http-connections = 128
             max-substitution-jobs = 128
             extra-platforms = aarch64-linux
+      - uses: DeterminateSystems/magic-nix-cache-action@main
       - name: Build system
         run: |
           nix build --system ${{ matrix.machine.platform }} .#otb-dev
-          nix build --system ${{ matrix.machine.platform }} .#otb