ファイルツール
PDFをパスワード保護
PDFをAES-256で暗号化し、閲覧権限と開くパスワードを設定します。
Your files are processed locally in your browser and never uploaded.
Your files are processed locally in your browser and never uploaded.
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使い方
- Choose a readable PDF. If it is already encrypted, enter its current password too.
- Enter and confirm a new password, optionally generate a strong one and set reader permissions.
- Protect the PDF and download the verified AES-256 result.
おすすめの用途
- Private reports and invoices
- Sharing documents with a known recipient
- Restricting casual edits or copying
Private, local PDF processing
BrightTools reads the selected PDF in your browser and never uploads it. File contents, names and passwords are not sent to analytics. A shared 50 MB and 200-page safety limit keeps memory use predictable on phones and desktops.
Quality and validation
Compression renders each page at a bounded resolution, encodes it as JPEG and checks the real output bytes. Target-size pages use a finite coarse-to-fine search; they never delete pages or create blank or damaged PDFs. The result is reparsed to confirm page count and page dimensions before download.
Related PDF tools
Need to prepare a document first? Merge PDFs, split pages, organize pages, convert an image to PDF or export a PDF to images.
注意点
Reader permissions are enforced by PDF viewers and cannot absolutely prevent copying, printing or screenshots. Keep the password safe; BrightTools cannot recover it.
よくある質問
Is this real PDF encryption?
Yes. The browser loads qpdf WebAssembly on this page and writes standard AES-256 PDF encryption, not a ZIP password.
Are passwords stored?
No. Password fields use autocomplete=off and remain in memory only until you reset or leave the page.
Can I protect an already encrypted PDF?
Yes, provide its current opening password before setting the new one.