# PDF Signature Validator > PDF Signature Validator (pdfsigncheck.com, formerly "PDF SignCheck") is a free online tool that validates digital signatures in PDF files. It checks PKCS#7/CMS and PAdES signatures, verifies the signer's X.509 certificate chain against 80+ trusted root Certificate Authorities, detects any modification made after signing, and returns a copy of the PDF stamped "Signature valid". A PDF signature validator answers one question: is this signed PDF genuine? It confirms (1) integrity — the document hash over the signed byte range still matches, so nothing changed after signing; (2) authenticity — the signing certificate chains to a trusted CA such as CCA India or an eIDAS qualified trust service provider; and (3) validity — the certificate was valid at signing time. Key facts: - Price: free daily validations without sign-up; optional one-time $4.99 top-up for 100 extra credits and an ad-free experience. - Privacy: files are processed in server memory over HTTPS, never written to disk, never stored, and discarded after the result is returned. - Common use: fixing Adobe Acrobat's "Signature Not Verified" / "Validity Unknown" warning on Indian government documents (Aadhaar, DigiLocker, e-District certificates, ITR-V) and on eIDAS, UAE Pass, Singpass and US ESIGN signed PDFs. - Also available as an Android app and as an MCP server for AI assistants. --- ## Core Features - **Cryptographic Validation**: Verifies PKCS#7/CMS digital signatures and computes document hashes against byte ranges to detect any modifications after signing. - **Auto-Trust Certification**: Automatically validates the certificate chain against 82 trusted root Certificate Authorities (CAs) from the Mozilla CA trust store. - **Verified PDF Output**: Stamps the document with a visual "Signature valid" badge matching Adobe Acrobat's design, removing the need for manual "trust certificate" configuration. - **PDF Ink/Toner Cost Estimator**: Scans pixel-level CMYK ink/toner coverage per page to calculate standard printing/paper costs and produces ink-saver optimized variants (Grayscale, Draft, Image-Stripped). - **PDF Reading Time Inserter**: Automatically detects chapters and sections in any PDF and embeds per-section reading duration stamps (⏱ X min read) directly into the page layouts. - **PDF Copy-Paste Text Fixer**: Reconstructs broken text copied from PDF files by removing arbitrary layout line breaks, rejoining word hyphenations split across line breaks, fixing common typography ligatures, and cleaning up spaces. - **PDF Placeholder Replacer**: Scans PDF text layers for Lorem Ipsum, TBD variables, underscores, or fillable form fields, and overlays text (standard or handwritten cursive styles) or signature images over covered whiteout zones. - **PDF Redactor**: Censor and blackout private text, metadata, signatures, and regions (like photos or SSNs) permanently. Sanitizes internal PDF structures by deleting actual character bytes instead of just overlaying visual boxes. - **PDF Protector**: Protect PDF documents with 128-bit password encryption (User/Open Password and Owner Password) and granular access permissions (printing, copying, editing, annotating). - **Zero-Storage Privacy**: Files are processed purely in-memory and immediately discarded. No documents are stored on server disks. - **No Sign-Up Required**: Fast, free one-off verifications out-of-the-box. --- ## Supported Document Types - UIDAI Aadhaar Cards (e-Aadhaar) - DigiLocker certificates (CBSE marksheets, driving licenses, vehicle registrations, PAN cards) - Income Tax returns (ITR-V acknowledgements) - Caste, Income & Domicile certificates (e-District portals) - NFSA Ration Cards - Birth & Death certificates (CRS) - MCA incorporation certificates - Any PKCS#7/CMS digitally signed PDF --- ## Site Map & Key Resources - [PDF Signature Validator Home](https://pdfsigncheck.com): The interactive web app containing the PDF drag-and-drop checker, verification chain display, and pricing list. - [PDF Ink/Toner Cost Estimator](https://pdfsigncheck.com/pdf-ink-toner-cost-estimator): Drag-and-drop PDF cost analyzer to scan pixel-level CMYK ink/toner coverage and generate print-saver eco PDFs. - [PDF Reading Time Inserter](https://pdfsigncheck.com/pdf-reading-time-inserter): Auto-detect chapter structures and embed estimated reading duration stamps per section directly into any PDF. - [PDF Copy-Paste Text Fixer](https://pdfsigncheck.com/pdf-copy-paste-text-fixer): Online tool to fix broken lines, hyphens, spaces, and ligatures in copied PDF text. - [PDF Placeholder Replacer](https://pdfsigncheck.com/pdf-placeholder-replacer): Browser-side PDF scanner to find and replace placeholder texts, type on PDF forms, or overlay signature images. - [PDF Redactor](https://pdfsigncheck.com/pdf-redactor): Drag-and-drop secure PDF redactor to permanently censor and blackout private text, numbers, or drawing regions. - [PDF Protector](https://pdfsigncheck.com/pdf-protector): Drag-and-drop PDF protector to encrypt documents with 128-bit password protection and custom permissions. - [PDF Compressor](https://pdfsigncheck.com/pdf-compressor): Drag-and-drop PDF compressor to reduce file size with configurable quality levels and zero text quality degradation. - [About PDF Signature Validator](https://pdfsigncheck.com/about): Company background, technical stack, security commitments, and founder information. - [Pricing](https://pdfsigncheck.com/pricing): Compare Guest (free), Free Account, and Pro Top-up ($4.99 one-time) plans. - [How to Verify PDF Digital Signatures](https://pdfsigncheck.com/how-to-verify-pdf-digital-signature): Complete step-by-step guide with IT Act 2000 citations and legal framework. - [Why Adobe Shows "Signature Not Verified"](https://pdfsigncheck.com/why-adobe-shows-signature-not-verified): Technical explainer on AATL vs CCA India trust lists. - [DigiLocker PDF Signature Verification](https://pdfsigncheck.com/digilocker-pdf-signature-verification): Guide for verifying Indian government documents from DigiLocker. - [Advertise on PDF Signature Validator](https://pdfsigncheck.com/advertise): Options to sponsor advertisement slots targeting tech and legal professionals. - [Feature Requests](https://pdfsigncheck.com/feature-request): Submit and vote on feature requests. - [MCP Server Integration Guide](https://pdfsigncheck.com/mcp-server): Developer documentation on connecting PDF Signature Validator tools to ChatGPT, Claude Desktop, and Cursor via the Model Context Protocol (MCP) gateway. - [MCP API Endpoint](https://pdfsigncheck.com/mcp): Streamable HTTP MCP server gateway for AI assistants. Requires API key authentication. - **Global Signature Verification Guides**: - [US ESIGN & UETA Signatures](https://pdfsigncheck.com/verify-esign-pdf-signature) - [UK eIDAS Signatures](https://pdfsigncheck.com/verify-uk-eidas-signature) - [France eIDAS Signatures](https://pdfsigncheck.com/verify-france-pdf-signature) - [EU eIDAS Signatures](https://pdfsigncheck.com/verify-eidas-digital-signature) - [Singapore Singpass Signatures](https://pdfsigncheck.com/verify-singpass-pdf-signature) - [UAE Pass Signatures](https://pdfsigncheck.com/verify-uae-pass-signature) - **Indian State e-District Guides**: - [Uttar Pradesh](https://pdfsigncheck.com/verify-uttar-pradesh-certificate-digital-signature), [Maharashtra](https://pdfsigncheck.com/verify-maharashtra-certificate-digital-signature), [Bihar](https://pdfsigncheck.com/verify-bihar-certificate-digital-signature), [Delhi](https://pdfsigncheck.com/verify-delhi-certificate-digital-signature), [Madhya Pradesh](https://pdfsigncheck.com/verify-madhya-pradesh-certificate-digital-signature), [West Bengal](https://pdfsigncheck.com/verify-west-bengal-certificate-digital-signature), [Rajasthan](https://pdfsigncheck.com/verify-rajasthan-certificate-digital-signature), [Tamil Nadu](https://pdfsigncheck.com/verify-tamil-nadu-certificate-digital-signature), [Gujarat](https://pdfsigncheck.com/verify-gujarat-certificate-digital-signature), [Karnataka](https://pdfsigncheck.com/verify-karnataka-certificate-digital-signature), [Andhra Pradesh](https://pdfsigncheck.com/verify-andhra-pradesh-certificate-digital-signature), [Telangana](https://pdfsigncheck.com/verify-telangana-certificate-digital-signature), [Kerala](https://pdfsigncheck.com/verify-kerala-certificate-digital-signature), [Odisha](https://pdfsigncheck.com/verify-odisha-certificate-digital-signature), [Punjab](https://pdfsigncheck.com/verify-punjab-certificate-digital-signature), [Haryana](https://pdfsigncheck.com/verify-haryana-certificate-digital-signature), [Assam](https://pdfsigncheck.com/verify-assam-certificate-digital-signature), [Jharkhand](https://pdfsigncheck.com/verify-jharkhand-certificate-digital-signature), [Chhattisgarh](https://pdfsigncheck.com/verify-chhattisgarh-certificate-digital-signature), [Himachal Pradesh](https://pdfsigncheck.com/verify-himachal-pradesh-certificate-digital-signature), [Uttarakhand](https://pdfsigncheck.com/verify-uttarakhand-certificate-digital-signature), [Goa](https://pdfsigncheck.com/verify-goa-certificate-digital-signature), [Sikkim](https://pdfsigncheck.com/verify-sikkim-certificate-digital-signature), [Tripura](https://pdfsigncheck.com/verify-tripura-certificate-digital-signature), [Arunachal Pradesh](https://pdfsigncheck.com/verify-arunachal-pradesh-certificate-digital-signature), [Manipur](https://pdfsigncheck.com/verify-manipur-certificate-digital-signature), [Meghalaya](https://pdfsigncheck.com/verify-meghalaya-certificate-digital-signature), [Mizoram](https://pdfsigncheck.com/verify-mizoram-certificate-digital-signature), [Nagaland](https://pdfsigncheck.com/verify-nagaland-certificate-digital-signature) --- ## Pricing Plans & Rate Limits - **Guest Plan**: Free, no registration required. Allows **2 uses per tool per day** (signature verifications, dark mode conversions, duplicate page removals, font changes, ink/toner estimations, reading time insertions, copy-paste text fixes, placeholder replacements, redacting, protecting). - **Free Account**: Free with email login. Allows **5 uses per tool per day** (3 for Redact and Protect). - **Pro Top-up Pack**: One-time payment of $4.99. Adds **100 credits for each tool** with lifetime validity, removes ads, enables priority queues, and provides lifetime updates. - *Note: Global rate limit is 10 requests per minute per IP. Maximum file size is 50 MB.* --- ## Technical Specifications & Details - **Cryptographic Engine**: Built on `node-forge` (for PKCS#7 parsing/hash checking) and `pdf-lib` (for PDF incremental saving/visual stamps). - **Certificate Verification**: Check chains up to root CAs. Verification bypasses Adobe's proprietary Approved Trust List (AATL) restrictions by programmatically confirming CA signatures. - **Legal Framework**: Digital signatures validated are legally recognized under the Information Technology Act, 2000 (Sections 3, 5, 35) of India. --- ## Contact - Email: hi@pdfsigncheck.com - Founded by: Minhaj