免费 · 文件、办公与表格
文件类型识别（魔数）.
根据文件开头的字节判断其真实类型（PDF、图片、视频、压缩包、Office 文档、程序等 50 多种），识别被改名或伪装的文件。
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使用方法: 文件类型识别（魔数）
输入数据或选择文件，调整设置并生成结果。复制或下载之前，请检查结果。
限制与支持格式
输入内容在您的设备上处理。
英语技术说明
Text formats (CSV, Markdown, source code) look alike and are reported as plain text. Not an antivirus. Everything is calculated in your browser; nothing you type is uploaded.
Each format starts with characteristic bytes (“magic numbers”): %PDF for PDF, 89 50 4E 47 for PNG, PK plus word/ for DOCX, MZ for Windows programs. The extension is then compared with the content.
A file named invoice.pdf.exe starting with “MZ” is reported as a Windows program with a double-extension warning.