＂梯子代理：网络安全中的隐蔽通信工具＂

User wants a strategy article written in Chinese, with specific formatting requirements and content guidelines, including using Chinese throughout, bolding the term '梯子代理' (proxy) at least twice, using tags for subheadings, starting with a line of keywords, followed by a description, and having a minimum of 5000 words. The article should be rich in content, with keywords appearing multiple times, and keywords should not be repeated in the title. The title should be relevant and rich in content, and the article should not contain any web addresses.