모든 VPS 또는 클라우드 제공자에서 첫 SSH 연결의 MITM 막기

The conventional Trust On First Use (TOFU) model leaves initial SSH connections vulnerable to MITM attacks, while injecting long-term keys via cloud-init userdata risks exposure through metadata services or SSRF. ssh-init-vm mitigates these risks by using temporary keys for the first handshake and relying on OpenSSH host key rotation to establish secure long-term trust. This provides a robust, provider-agnostic security layer that prevents sensitive key leakage in cloud environments.