diff --git a/deploy/nas/README.md b/deploy/nas/README.md
index 561f3f02..264aaf16 100644
--- a/deploy/nas/README.md
+++ b/deploy/nas/README.md
@@ -48,7 +48,10 @@ SSH 或 `sudo` 密码。安装时要完成以下动作：
    `edge`。更新服务只读取该目录，个人账号不能修改 root 更新流程。
 2. 将 `update-plainleaf.sh` 安装为 `/usr/local/sbin/plainleaf-update`。
 3. 将 systemd 单元安装到 `/etc/systemd/system/plainleaf-update.service`。
-4. 安装本机 SSH 公钥，让发布脚本可用 `BatchMode` 连接 NAS。
+4. 生成专用的 `~/.ssh/plainleaf_zspace_ed25519`，将公钥安装到 NAS。授权行使用
+   forced-command，并禁用端口转发、Agent 转发、PTY 和 X11；这把密钥只能触发
+   Plainleaf 更新，不能登录 Shell。发布脚本还会开启 `BatchMode` 和
+   `IdentitiesOnly`，不会回退到密码或其他密钥。
 5. 安装 `plainleaf-update.sudoers`，其中只有一条受限规则，只允许 NAS 账号免密启动
    `plainleaf-update.service`，不能免密执行其他 root 命令。
 6. 执行 `systemctl daemon-reload`，再手动启动一次服务，确认拉取、重建和健康检查
diff --git a/deploy/nas/deployment.test.ts b/deploy/nas/deployment.test.ts
index 988a6250..221aa095 100644
--- a/deploy/nas/deployment.test.ts
+++ b/deploy/nas/deployment.test.ts
@@ -39,6 +39,9 @@ test("NAS deployment follows the Gitea edge image", () => {
   expect(publisher).toContain('--tag "${IMAGE_REPOSITORY}:edge"');
   expect(publisher).toContain("--push");
   expect(publisher).toContain("-o BatchMode=yes");
+  expect(publisher).toContain("-o IdentitiesOnly=yes");
+  expect(publisher).toContain('-i "$NAS_IDENTITY_FILE"');
+  expect(publisher).toContain("plainleaf_zspace_ed25519");
   expect(publisher).toContain(
     "sudo -n /usr/bin/systemctl start plainleaf-update.service",
   );
diff --git a/scripts/publish-nas-image.sh b/scripts/publish-nas-image.sh
index 665dfe9b..d0d9846c 100755
--- a/scripts/publish-nas-image.sh
+++ b/scripts/publish-nas-image.sh
@@ -6,6 +6,7 @@ readonly IMAGE_REPOSITORY="gitea.aichickenfarm.cn/wushenghua/plainleaf"
 readonly NAS_HOST="${PLAINLEAF_NAS_HOST:-192.168.31.68}"
 readonly NAS_PORT="${PLAINLEAF_NAS_PORT:-10000}"
 readonly NAS_USER="${PLAINLEAF_NAS_USER:-13616066635}"
+readonly NAS_IDENTITY_FILE="${PLAINLEAF_NAS_IDENTITY_FILE:-${HOME}/.ssh/plainleaf_zspace_ed25519}"
 
 repo_root="$(git rev-parse --show-toplevel)"
 cd "$repo_root"
@@ -20,6 +21,12 @@ if ! docker buildx version >/dev/null 2>&1; then
   exit 1
 fi
 
+if [[ ! -r "$NAS_IDENTITY_FILE" ]]; then
+  echo "发布已取消：缺少 Plainleaf 专用 SSH 密钥 ${NAS_IDENTITY_FILE}。" >&2
+  echo "请先完成 NAS 主动更新的一次性安装。" >&2
+  exit 1
+fi
+
 git_sha="$(git rev-parse HEAD)"
 short_sha="$(git rev-parse --short=8 HEAD)"
 
@@ -41,6 +48,8 @@ echo "镜像推送完成，正在触发 NAS 更新。"
 ssh \
   -o BatchMode=yes \
   -o ConnectTimeout=8 \
+  -o IdentitiesOnly=yes \
+  -i "$NAS_IDENTITY_FILE" \
   -p "$NAS_PORT" \
   "${NAS_USER}@${NAS_HOST}" \
   "sudo -n /usr/bin/systemctl start plainleaf-update.service"