diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6c2569eeb..081dd2008 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -175,7 +175,7 @@ jobs:
 
       - name: Sign image with a key
         run: |
-          cosign sign --yes --key env://COSIGN_PRIVATE_KEY ghcr.io/fkie-cad/logprep:py${{ matrix.python-version }}-${{ github.head_ref }}@${ DIGEST }
+          cosign sign --yes --key env://COSIGN_PRIVATE_KEY ghcr.io/fkie-cad/logprep:py${{ matrix.python-version }}-${{ github.head_ref }}@${DIGEST}
         env:
           COSIGN_PRIVATE_KEY: ${{ secrets.COSIGN_PRIVATE_KEY }}
           COSIGN_PASSWORD: ${{ secrets.COSIGN_PASSWORD }}