or click to select
Upload PDF 拖拽或点击上传PDF文件，文件仅在浏览器本地处理。/ Drag and drop or click to select a PDF file.
Set Password 输入打开密码（必填），可选设置权限密码限制打印/编辑。/ Enter open password (required) and optional permissions password.
Encrypt & Download 点击「加密PDF」，完成后下载加密后的文件。所有处理在浏览器本地完成。/ Click encrypt, then download. All processing is local.
Contracts：发送敏感合同前添加密码保护，确保只有授权人员可查看。/ Protect confidential contracts before sharing.
Privacy：对身份证扫描件、银行对账单等敏感PDF添加保护。/ Secure personal ID scans and bank statements.
Academia：提交论文前添加密码，防止未授权传播。/ Protect research papers before submission.
Internal：加密公司内部传阅的重要文件如薪酬报表等。/ Encrypt internal company documents.
PDF Encryption Standards: PDF supports RC4 and AES encryption. This tool uses pdf-lib for AES-256 encryption. Password complexity directly affects security - use at least 8 characters with mixed types.
Yes, with the password. For removing protection, use a PDF unlock tool. Remember your password - it cannot be recovered.
No. Everything runs locally in your browser. Files never leave your device.
Open password (required to view) and permissions password (restricts print/copy/edit). Set one or both.
Up to 100MB recommended. Limited by browser memory. Use desktop software for larger files.
Yes. Standard PDF encryption works with Adobe Acrobat, browser viewers, and mobile PDF apps.