涂黑 PDF 中的敏感信息
在要去除的部分画框——永久去除，而不只是遮盖。
使用方法
1. 上传你的 PDF。2. 在任意页面上，为每处要涂黑的内容画一个框。3. 下载——这些区域会被永久移除，而不只是遮盖。
内容是真的被移除了，还是只是被黑框盖住？
是真正移除。你涂黑的页面会先将标记区域涂成黑色，再整体转换为一张平面图像——因此下面不会留下任何可被复制、选中或恢复的文字或隐藏数据。这与那些只是在文字上方画一个框、别人可以删除黑框或复制下方文字看到原文的工具完全不同。
这会影响我没有标记的页面吗？
不会——只有至少含一个涂黑区域的页面会被转换为图像。你没有动过的页面会保留原始文字、清晰度和文件大小。
涂黑后的页面文字还能被选中或搜索到吗？
不能，这是刻意设计的——只要页面上有任何内容被涂黑，整页就会变成一张平面图像，这正是确保隐藏内容无法被恢复的关键。
Can I undo a redaction after I've downloaded the file?
No. Once you download, the redacted pages are baked into a new PDF and there's no getting the original content back. You can still remove or adjust a box before you download, though — nothing is final until you export.
Can I search for a word and redact every instance of it automatically?
No — this tool only redacts what you draw a box over. If a name or number appears five times in your PDF, you have to box out all five yourself. There's no find-and-redact-all feature.
Will my file get bigger after redacting?
Usually, yes. Any page with a redaction on it gets turned into a compressed image instead of live text, so even redacting one line can make that page's file size bigger than it was originally — that's the tradeoff for making the content truly unrecoverable.
Does redacting also strip hidden metadata, like the author's name or document title?
Yes, as a side effect. The output is built as a brand-new PDF rather than a patched copy of your original, so metadata like the author and title from your source file doesn't carry over.