How does PDF SignCheck verify a PDF digital signature?

PDF SignCheck cryptographically validates the digital signatures embedded in PDF documents. It checks that the document has not been tampered with after signing, verifies the signer's certificate chain against trusted root Certificate Authorities (CAs), and outputs a stamped PDF with a "Verified ✓" badge — similar to clicking "Trust this certificate" in Adobe Acrobat.

Is my PDF document stored or saved during digital signature verification?

No. Your file is processed entirely in memory on the server. It is never written to disk, never stored in any database, and is discarded immediately after the verified PDF is returned to your browser. We take privacy seriously — your documents remain yours.

What types of PDF digital signatures and certificates are supported?

PDF SignCheck supports PDFs that contain PKCS#7 / CMS digital signatures — the standard used by government portals, official certificate authorities, and digital signing platforms. This includes documents from DigiLocker, e-District, MCA, UIDAI, and similar government services worldwide.

Why does Adobe Acrobat Reader display a PDF signature as "Not Verified"?

Adobe Acrobat only trusts certificates from its own Adobe Approved Trust List (AATL). Many government and institutional signers are not on that list. Our tool auto-trusts the signer's certificate after cryptographic verification — exactly what Adobe asks you to do manually when you click "Trust this certificate." The downloaded verified PDF includes a visual stamp so it's clear the signature has been validated.

Is the online PDF signature verification process cryptographically secure?

Yes. We perform full PKCS#7 signature verification: we extract the signed hash from the signature, independently compute the hash of the document's byte ranges, and compare them. We also validate the certificate chain up to a trusted root CA from the Mozilla CA trust store. This is the same process that Adobe Acrobat and other professional PDF tools use.

Are there daily or rate limits for PDF cryptographic verification?

To prevent abuse, we rate-limit to 10 requests per minute per IP address. The maximum file size is 50 MB. These limits are sufficient for normal usage. If you need higher throughput for enterprise use, please contact us.

Which Indian government certificates and portals are supported?

PDF SignCheck fully supports digital signature verification for official Indian government certificates. This includes UIDAI Aadhaar Cards, state e-District certificates (such as Caste, Income, Domicile, and Birth/Death certificates), DigiLocker-issued PDF documents, NFSA Ration Cards, Income Tax / PAN documents, and any official PDF signed via CCA India (Controller of Certifying Authorities) root credentials.

How do I resolve the "Signature Not Verified" or "Signature Not Checked" warning on Aadhaar or Caste certificates?

Simply upload your signed PDF to PDF SignCheck. Our system extracts the digital signature, cryptographically validates the hash integrity against trusted root certificates, and generates a stamped PDF. When you download this verified document, the signature will show as valid, making it suitable for direct submission.

PDF Protector

Password Protect & Encrypt PDFs

Add owner and user passwords to control who can open, print, copy, or edit your PDF documents. Processed securely in-memory — your files never leave your device unprotected.

EncryptedRC4-128 Protection

PermissionsGranular Access Control

0B StoredProcessed In-Memory

Daily Limit

Upload your PDF

Drag and drop your file here, or click to browse

.pdf·up to 50 MB

Zero-Knowledge Privacy

Files are processed strictly in secure memory modules inside your local browser. No server storage.

Cryptographic Standards

Fully compliant with IETF RFC 5652 (CMS), Adobe PDF specs, eIDAS, and Controller of Certifying Authorities (CCA).

Verify Anonymously

No personal registration or document tracking is required. Verify up to 2 files daily as guest.

Detailed Audit Trails

Generates downloadable, verified PDFs with structural signature stamps and trust summaries.

Edge Sandbox Security

Verification executes inside sandboxed browser modules to ensure isolated document handling.

Zero Data Logging

Absolutely no logging of files, names, email contents, or signature details. Pure privacy.

Process

How to Protect a PDF in 3 Easy Steps

Add password protection and encryption to your PDF documents securely.

Upload Document

Drag and drop your PDF file into the dropzone above, or click browse to choose a file up to 50 MB.

Set Passwords & Permissions

Enter an owner password to restrict editing/printing, or a user password to restrict opening. Configure granular permissions.

Apply & Download

Click Apply Protection to encrypt your PDF with the specified settings, then download the secured file.

Features

Enterprise-Grade PDF Encryption

Protect your sensitive documents with professional security controls.

Dual Password System

Set an Owner Password to restrict actions, and/or a User Password to require authentication before the document can even be opened.

Granular Permission Controls

Fine-tune exactly what recipients can do: printing, copying text, editing content, and adding annotations — each toggled independently.

RC4-128 Encryption

Industry-standard encryption supported by all major PDF readers: Adobe Acrobat, macOS Preview, Chrome, Firefox, and more.

Zero Stored Files

Your PDF is processed in-memory and returned immediately. No files are stored, copied, or logged on our servers.

Support

Frequently Asked Questions

Answers to common questions about password protecting and encrypting PDFs.

What is the difference between Owner and User passwords?

The Owner Password controls what actions are allowed on the PDF (printing, copying, editing). Anyone can open the PDF but restrictions apply. The User Password (also called the "open" password) requires recipients to enter it just to view the document.

Is my PDF stored on your servers?

No. The PDF is processed securely in-memory on our server, encrypted with your specified passwords, and returned immediately. We do not store, copy, or log your files.

What encryption method is used?

We use RC4-128 encryption which is widely supported by all major PDF readers including Adobe Acrobat, Preview on macOS, Chrome, and Firefox.

Can I set permissions without a user password?

Yes. If you only set an Owner Password, the PDF will open without a password prompt, but the specified restrictions (like no printing or no copying) will be enforced by compliant PDF readers.

What are the daily usage limits?

Guests get 2 free protection operations per day. Free registered accounts get 3 operations, and Top-up Credits users get up to 100 operations.

Suite

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Password Protect & Encrypt PDFs

Zero-Knowledge Privacy

Cryptographic Standards

Verify Anonymously

Detailed Audit Trails

Edge Sandbox Security

Zero Data Logging

How to Protect a PDF in 3 Easy Steps

Upload Document

Set Passwords & Permissions

Apply & Download

Enterprise-Grade PDF Encryption

Dual Password System

Granular Permission Controls

RC4-128 Encryption

Zero Stored Files

Frequently Asked Questions

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