diff --git a/builder/action.yml b/builder/action.yml
index 896ebaf..742d45c 100644
--- a/builder/action.yml
+++ b/builder/action.yml
@@ -25,6 +25,9 @@ inputs:
   api_auth_token:
     description: 'api_auth_token if needed to download base images'
     required: false
+  gpg_sign_key:
+    description: 'gpg key to sign images'
+    required: false
 
 #outputs:
 #  hashes:
@@ -44,3 +47,4 @@ runs:
         INPUT_SB_DB_KEY: ${{ inputs.sb_db_key }}
         INPUT_SB_DB_PEM: ${{ inputs.sb_db_pem }}
         INPUT_API_AUTH_TOKEN: ${{ inputs.api_auth_token }}
+        GPG_SIGN_KEY: ${{ secrets.gpg_sign_key }}