diff --git a/templates/gitlab-ci-docker.yml b/templates/gitlab-ci-docker.yml
index d9106c1bfa09077efd392570a35cedad910f7a50..f8e47f0d6bcf8e9bc9389f75662646a89e4ddf52 100644
--- a/templates/gitlab-ci-docker.yml
+++ b/templates/gitlab-ci-docker.yml
@@ -854,11 +854,11 @@ stages:
   }
 
   configure_cosign_private_key() {
-    if [[ -z ${DOCKER_COSIGN_PRIVATE_KEY:-$COSIGN_PRIVATE_KEY} ]]
+    if [[ -z "${DOCKER_COSIGN_PRIVATE_KEY:-$COSIGN_PRIVATE_KEY}" ]]
     then
       fail "Cosign private key is not defined"
     fi
-    if [[ -f ${DOCKER_COSIGN_PRIVATE_KEY:-$COSIGN_PRIVATE_KEY} ]]
+    if [[ -f "${DOCKER_COSIGN_PRIVATE_KEY:-$COSIGN_PRIVATE_KEY}" ]]
     then
       docker_cosign_private_key=${DOCKER_COSIGN_PRIVATE_KEY:-$COSIGN_PRIVATE_KEY}
     else