diff --git a/.forgejo/workflows/update-lock.yml b/.forgejo/workflows/update-lock.yml
index d335359..40a82e3 100644
--- a/.forgejo/workflows/update-lock.yml
+++ b/.forgejo/workflows/update-lock.yml
@@ -18,9 +18,22 @@ jobs:
         run: |
           git config --global user.name "ukubot"
           git config --global user.email "bot@uku.moe"
+          git config --global user.signingkey "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJophqKVpoaeFJP1Wf3SEcfOMObogY6738lx2Ng+LGcQ ukubot"
+          git config --global gpg.format "ssh"
+
+      - name: Setup SSH Key
+        run: |
+          mkdir -p /home/runner/.ssh
+          echo "${{ secrets.SSH_KEY }}" > /home/runner/.ssh/action
+          chmod 600 /home/runner/.ssh/action
+
+          ssh-agent -a /tmp/ssh_agent.sock > /dev/null
+          ssh-add /home/runner/.ssh/action
 
       - name: Update lockfile
         id: update_lockfile
+        env:
+          SSH_AUTH_SOCK: /tmp/ssh_agent.sock
         run: |
           git checkout -b "update-lock-$(date -I)"
           nix flake update --commit-lock-file