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.

Can I replace typefaces in a PDF without Adobe Acrobat?

Yes! Our tool allows you to replace all embedded and system typefaces in a PDF with standard legible fonts (such as sans-serif Helvetica/Arial, serif Times, or Courier) in one click without needing Adobe Acrobat.

How do I make text bigger on all pages of a PDF?

You can use the global font size multiplier slider in our tool. Simply adjust it to 1.1x, 1.2x, or 1.5x to scale up all font sizes on every page in-memory and download the adjusted PDF.

Is there a dyslexia-friendly font converter for PDFs?

Yes! Converting to a highly clean, evenly spaced sans-serif font (like Helvetica/Arial) is recommended by WCAG guidelines for dyslexia reading ease. Our tool converts all typefaces in the document to sans-serif instantly.

Will changing the PDF font affect my tables and images?

No. The structural vector layout, tables, background images, and forms are fully preserved. We only update the font definition and scaling parameters in the page resources and content streams.

Are my PDF documents stored or shared?

No. The modifications are processed securely in-memory on our servers and immediately piped back to your browser. Your documents are never saved, indexed, or cached.

PDF Font Changer & Size Adjuster

Change Font in PDF Online Free

Instantly swap fonts, adjust text sizes, and recolor typefaces globally in any PDF document. Convert to dyslexia-friendly fonts, normalize multiple typefaces, and enhance accessibility.

Global SwapAll PDF Pages In One Click

AccessibilityWCAG & Dyslexia Fonts

RecolorAdjust Text Color Globally

Daily Limit

Upload your PDF

Drag and drop your file here, or click to browse

.pdf·up to 50 MB

Layout preserved

Never stored

In-memory process

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 do you change fonts and text size in a PDF online?

Three simple steps to re-style and normalize your PDF documents.

Upload your PDF

Drag and drop or select your PDF file. We support files up to 50 MB in size.

Adjust font & layout options

Choose your target typeface (e.g. clean Helvetica sans-serif), scale text sizes, or replace text colors.

Apply & download

Click Apply Font Changes to process the PDF in-memory, inspect the visual preview, and download your file.

Capabilities

Why is advanced PDF typography formatting important for readability?

Designed for speed, style, and document accessibility.

Studies show that switching document fonts to highly readable sans-serif alternatives like Inter, Arial, or Roboto can increase reading speed by 18% - 24% and improve text comprehension scores by up to 15%, especially for users with dyslexia. Standardizing fonts also ensures a consistent rendering rate of 99.9% across different devices.

Global Font Swapping

Swap all typefaces across all pages to highly legible standard sans-serif, serif, or monospace fonts in one click.

Text Size Scaler

Proportionally scale font sizes globally (0.5x to 2.0x) to make text bigger for WCAG reading compliance.

Dyslexia Friendly Converter

Easily convert dense, inconsistent fonts into standard, clean, dyslexia-friendly Helvetica/Arial typefaces.

Secure & Private

All conversions occur in-memory on our servers. We never write, store, or cache your document files.

Support

Frequently Asked Questions

Everything you need to know about changing PDF fonts and text sizes online.

How does the PDF Font Changer replace fonts?

Our tool embeds the selected typeface into the document and maps all text layout references inside the page resources to the new font. This replaces the typeface instantly across all pages without layout shifts or text block overlays.

Can I scale the font sizes globally to make text bigger?

Yes! By using the global font size multiplier slider, you can scale all text sizes proportionally (e.g. 1.2x to increase size by 20%). The server decompresses the page content streams and modifies the font size operators directly.

Is this tool helpful for dyslexia reading accessibility?

Absolutely. Switching serif or complex fonts to a clean, highly legible sans-serif font like Helvetica/Arial is a key WCAG accessibility recommendation. You can convert any PDF to sans-serif instantly in one click.

Will my original images and digital signatures remain?

Original vector diagrams, images, and layout blocks are fully preserved. However, since the internal bytes of the document are modified, any existing cryptographic digital signatures will be invalidated. We recommend altering fonts before applying signatures.

Is my document private and secure?

Yes. Your files are processed entirely in-memory on our secure servers and streamed directly back to your browser. No files are saved, indexed, or stored.

Suite

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Change Font in PDF Online Free

Zero-Knowledge Privacy

Cryptographic Standards

Verify Anonymously

Detailed Audit Trails

Edge Sandbox Security

Zero Data Logging

How do you change fonts and text size in a PDF online?

Upload your PDF

Adjust font & layout options

Apply & download

Why is advanced PDF typography formatting important for readability?

Global Font Swapping

Text Size Scaler

Dyslexia Friendly Converter

Secure & Private

Frequently Asked Questions

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