diff --git a/unity-command/Dockerfile b/unity-command/Dockerfile
index 8b999d4..679884f 100644
--- a/unity-command/Dockerfile
+++ b/unity-command/Dockerfile
@@ -2,10 +2,6 @@
 ARG IMAGE=unityci/base:latest
 FROM ${IMAGE}
 
-ARG SERIAL
-ARG USERNAME
-ARG PASSWORD
-
 RUN apt update
 RUN apt install -y wget chromium-browser
 
@@ -16,6 +12,9 @@ COPY entrypoint.sh /
 RUN chmod +x /entrypoint.sh
 
 COPY scripts/. /scripts
-RUN bash /scripts/activate_license.sh ${SERIAL} ${USERNAME} ${PASSWORD}
+RUN --mount=type=secret,id=SERIAL \
+    --mount=type=secret,id=USERNAME \
+    --mount=type=secret,id=PASSWORD \
+    bash /scripts/activate_license.sh
 
 ENTRYPOINT ["/entrypoint.sh"]
\ No newline at end of file
diff --git a/unity-command/action.yaml b/unity-command/action.yaml
index 05042a3..14cd90d 100644
--- a/unity-command/action.yaml
+++ b/unity-command/action.yaml
@@ -44,14 +44,17 @@ runs:
     run: |
       CONTAINER=${{ steps.getContainer.outputs.container }}
 
-      docker build -t ${{ inputs.imageTag }} --build-arg IMAGE=$CONTAINER ${{ github.action_path }}
+      SERIAL="${{ inputs.serial }}" USERNAME="${{ inputs.email }}" PASSWORD="${{ inputs.password }}" \
+      # Activate the license on build.
+      docker build . --secret id=SERIAL,env=SERIAL --secret id=USERNAME,env=USERNAME --secret id=PASSWORD,env=PASSWORD \
+      -t ${{ inputs.imageTag }} --build-arg IMAGE=$CONTAINER ${{ github.action_path }}
     shell: bash
   - name: "Run Unity command."
     uses: act/unity/unity@master
     with:
-      serial: ${{ inputs.serial }}
-      email: ${{ inputs.email }}
-      password: ${{ inputs.password }}
+      # serial: ${{ inputs.serial }}
+      # email: ${{ inputs.email }}
+      # password: ${{ inputs.password }}
       command: ${{ inputs.command }}
       unityBuilder: ${{ inputs.unityBuilder }}
   - name: "Remove temporary image."
diff --git a/unity-command/scripts/activate_license.sh b/unity-command/scripts/activate_license.sh
index 16589d2..81100fe 100644
--- a/unity-command/scripts/activate_license.sh
+++ b/unity-command/scripts/activate_license.sh
@@ -1,13 +1,29 @@
 #!/bin/bash
-SERIAL=$1; EMAIL=$2; PASSWORD=$3;
+SERIAL=$1; USERNAME=$2; PASSWORD=$3;
 
-if [[ -z "$SERIAL" || -z "$EMAIL" || -z "$PASSWORD" ]]; then
+function check_path
+{
+    local SECRET_PATH="/run/secrets"
+    local ENV_NAME="$1"
+    local ENV_VALUE="${!ENV_NAME}"
+
+    local FILE_PATH="$SECRET_PATH/$ENV_NAME"
+    if [[ -z "$ENV_VALUE" && -f "$FILE_PATH" ]]; then
+        export $ENV_NAME=$(cat "$FILE_PATH")
+    fi
+}
+
+check_path SERIAL
+check_path USERNAME
+check_path PASSWORD
+
+if [[ -z "$SERIAL" || -z "$USERNAME" || -z "$PASSWORD" ]]; then
     exit 0
 fi
 
 #Activate Unity
 if [[ "$SERIAL" == "personal" ]]; then
-    UnityBuilder activate -i /usr/bin/unity-editor -u $EMAIL -p $PASSWORD
+    UnityBuilder activate -i /usr/bin/unity-editor -u $USERNAME -p $PASSWORD
 else
-    unity-editor $DEFAULT_ARGS -serial $SERIAL -username $EMAIL -password $PASSWORD
+    unity-editor $DEFAULT_ARGS -serial $SERIAL -username $USERNAME -password $PASSWORD
 fi
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