Digital Signature with Certificate
Sign PDFs with your own PKCS#12 certificate (.pfx/.p12). PAdES-compliant, verifiable in Adobe Acrobat. 100% browser-based.
Digitally sign PDF documents for free using your own PKCS#12 certificate (.pfx or .p12 file). HonestPDF creates PAdES-B-B compliant signatures entirely in your browser - your certificate, private key, and document never leave your device. The signed PDF is verifiable in Adobe Acrobat, Foxit Reader, and any PAdES-compatible viewer. Ideal for lawyers, accountants, doctors, and anyone with a qualified electronic signature certificate from an EU, Turkish, Brazilian, or Indian trust service provider.
Drag & drop your PDF here, or browse to choose a file
PDF only
①Select file→②Load Certificate→③Sign
Private
Stays on Device
Instant
Common Use Cases
- →Signing tax declarations and financial statements with a qualified certificate before submission to tax authorities
- →Digitally signing employment contracts and HR documents with your company's certificate for legal compliance
- →Lawyers signing court filings, powers of attorney, and client agreements with their bar association certificate
- →Doctors and healthcare professionals signing medical reports and prescriptions with their professional certificate
- →Auditors signing audit reports and compliance documents with their certified public accountant certificate
- →Submitting digitally signed documents to government portals that require qualified electronic signatures
Key Benefits:
- ✓100% Browser-Based - Your certificate, private key, and PDF never leave your device. Zero server uploads.
- ✓PAdES-B-B Compliant - Follows the European standard for advanced electronic signatures on PDF documents.
- ✓Adobe Acrobat Verifiable - Open the signed PDF in Adobe Acrobat, Foxit, or any PAdES reader to verify the signature.
- ✓Free Forever - No subscriptions, no per-signature fees, no watermarks. Because processing runs on your device, not our servers.
- ✓Any PKCS#12 Certificate - Works with certificates from any trust service provider (.pfx or .p12 format).
- ✓Multi-Language Support - Available in 20 languages for professionals worldwide.
Privacy First:
HonestPDF processes your digital signature entirely in your browser. Your PKCS#12 certificate, private key, and PDF document are never uploaded to any server. The private key is cleared from memory immediately after signing. This is the most secure way to digitally sign a PDF online.
Frequently Asked Questions
What is a digital signature with a certificate?
A digital signature with a certificate uses Public Key Infrastructure (PKI) to cryptographically bind a signer's identity to a document. Unlike simple e-signatures (drawing your name), it uses your private key from a PKCS#12 certificate (.pfx/.p12) to create a tamper-evident seal. The signature can be verified by anyone using the signer's public certificate, proving both identity and document integrity.
Is my certificate and private key safe with this tool?
Yes, completely. HonestPDF processes everything in your browser using JavaScript. Your .pfx/.p12 file is parsed locally using node-forge, and the private key is held only in browser memory during signing. It is never sent to any server, stored in localStorage, or persisted anywhere. The key is cleared from memory immediately after the signature is created.
Is the signature compliant with EU eIDAS regulation?
HonestPDF creates PAdES-B-B (PDF Advanced Electronic Signatures - Basic) compliant signatures. When used with a qualified certificate from an EU-recognized Trust Service Provider (QTSP), the resulting signature meets the requirements for a Qualified Electronic Signature (QES) under eIDAS. The signature is verifiable in Adobe Acrobat's Signature Panel.
Can I use my Turkish e-signature (e-imza) certificate?
Yes. If your Turkish e-signature provider (e.g., TürkTrust, E-Güven, KamuSM) issued you a .pfx or .p12 file, you can use it directly. Export the certificate from your smart card or USB token to a .pfx file using your provider's utility, then upload it to HonestPDF.
What certificate formats are supported?
HonestPDF supports PKCS#12 (.pfx and .p12) certificates. These are the most common portable certificate formats. If your certificate is on a smart card or USB token, you'll need to export it to .pfx format first using your certificate provider's software.
Can I verify the signed PDF in Adobe Acrobat?
Yes. Open the signed PDF in Adobe Acrobat and check the Signature Panel (View → Show Signature Panel). It will show the signer's name, signing time, and certificate details. If your signing certificate's root CA is in Adobe's AATL (Adobe Approved Trust List), the signature will show as valid automatically.
What is PAdES-T and when will timestamp support be available?
PAdES-T adds a trusted timestamp from an RFC 3161 Timestamp Authority (TSA) to prove when the signature was created. This is important for long-term validation. Timestamp support requires a server-side proxy to reach TSA services due to browser CORS restrictions, and will be added in a future update.
Is this different from the regular Sign PDF tool?
Yes, completely. The regular Sign tool adds visual-only electronic signatures (drawing, typing, or uploading an image). This Digital Signature tool creates cryptographic PKCS#7 signatures embedded in the PDF's signature dictionary, using your actual certificate and private key. Only the Digital Signature tool is verifiable in Adobe Acrobat's Signature Panel.
Can I use a self-signed certificate?
Yes, technically. HonestPDF will accept any valid PKCS#12 file. However, a self-signed certificate won't be trusted by PDF readers because it isn't issued by a recognized Certificate Authority. For legally binding signatures, use a certificate from a trusted CA or QTSP.
Does this tool work offline?
Yes. After the page loads, you can disconnect from the internet and the tool will continue to work. PDF parsing, certificate reading, and signature creation all happen locally in your browser with zero network dependency.