diff --git a/pipeline_service/__init__.py b/pipeline_service/__init__.py
index 3695bc5..82c7484 100644
--- a/pipeline_service/__init__.py
+++ b/pipeline_service/__init__.py
@@ -50,6 +50,8 @@ from .work_env import (
     run_remote_sandbox,
     run_in_work_env,
     ensure_remote_bwrap,
+    ensure_org_key,
+    get_org_pubkey,
 )
 
 __version__ = "3.5.0"
diff --git a/pipeline_service/work_env.py b/pipeline_service/work_env.py
index a6b1a5e..b606bdc 100644
--- a/pipeline_service/work_env.py
+++ b/pipeline_service/work_env.py
@@ -19,6 +19,7 @@ import shlex
 import shutil
 import asyncio
 import logging
+import subprocess
 
 logger = logging.getLogger("pipeline.work_env")
 
@@ -70,8 +71,12 @@ def _ssh_target(env: dict) -> str:
 
 
 def _ssh_common_args(env: dict) -> list:
-    """ssh/scp/rsync 共用的 SSH 参数。"""
-    args = ["-o", "StrictHostKeyChecking=no", "-o", "ConnectTimeout=10"]
+    """ssh/scp/rsync 共用的 SSH 参数。
+
+    StrictHostKeyChecking=accept-new：首次连接记录 host key，之后严格校验，
+    防 MITM（host key 变化会拒绝），替代原来的 =no（完全不校验）。
+    """
+    args = ["-o", "StrictHostKeyChecking=accept-new", "-o", "ConnectTimeout=10"]
     key = env.get("remote_key_path", "")
     if key:
         args += ["-i", key]
@@ -80,6 +85,48 @@ def _ssh_common_args(env: dict) -> list:
     return args
 
 
+# ── 机构独立 SSH key（每机构一把，防单点泄露） ────────────────
+
+SSH_KEYS_DIR = os.path.expanduser("~/.ssh/org_keys")
+
+
+def _org_key_dir(org_id: str) -> str:
+    """机构 key 目录（org_id sanitize 防路径穿越）。"""
+    safe = re.sub(r"[^a-zA-Z0-9_-]", "_", org_id or "")
+    if not safe:
+        safe = "_"
+    return os.path.join(SSH_KEYS_DIR, safe)
+
+
+def ensure_org_key(org_id: str) -> dict:
+    """确保机构有独立 SSH key pair（ed25519），没有则生成。
+
+    Returns: {"key_path", "pubkey_path", "pubkey"}
+    """
+    d = _org_key_dir(org_id)
+    os.makedirs(d, mode=0o700, exist_ok=True)
+    priv = os.path.join(d, "id_ed25519")
+    pub = priv + ".pub"
+    if not (os.path.exists(priv) and os.path.exists(pub)):
+        subprocess.run(
+            ["ssh-keygen", "-t", "ed25519", "-N", "", "-f", priv,
+             "-C", "pipeline-org-" + (re.sub(r"[^a-zA-Z0-9_-]", "_", org_id) or "_")],
+            check=True, stdout=subprocess.DEVNULL, stderr=subprocess.DEVNULL)
+        os.chmod(priv, 0o600)
+    pubkey = ""
+    if os.path.exists(pub):
+        with open(pub, "r", encoding="utf-8") as f:
+            pubkey = f.read().strip()
+    return {"key_path": priv, "pubkey_path": pub, "pubkey": pubkey}
+
+
+def get_org_pubkey(org_id: str) -> dict:
+    """获取机构 public key（供 admin 复制到远程主机 authorized_keys）。"""
+    info = ensure_org_key(org_id)
+    return {"ok": True, "org_id": org_id, "pubkey": info["pubkey"],
+            "key_path": info["key_path"]}
+
+
 # ── 远程配置安全校验 ───────────────────────────────────────
 
 _HOST_RE = re.compile(r"^[a-zA-Z0-9]([a-zA-Z0-9\-\.]*[a-zA-Z0-9])?$")
@@ -232,6 +279,11 @@ async def set_work_env(sor, owner_type: str, owner_id: str, mode: str,
         return {"ok": False, "error": "mode 必须是 local 或 remote"}
 
     remote_config = remote_config or {}
+    if owner_type == "org" and mode == "remote":
+        # 机构级远程：自动使用机构独立 key（每机构一把，防单点泄露），
+        # 不允许 admin 指定任意 key
+        _key_info = ensure_org_key(owner_id)
+        remote_config["remote_key_path"] = _key_info["key_path"]
     if mode == "remote":
         err = _validate_remote(remote_config)
         if err: