PDF digital signature

Add or verify digital signature online for free

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Digital signatures provide authentication by ensuring that the recipient can verify the authenticity of the document. A digital signature also ensures the integrity of the document by detecting any unauthorized changes made after signing, making it difficult for fraudsters to tamper with the document.

Digital signatures provide non-repudiation, meaning the signer cannot deny his involvement in signing a document, which is essential in legal and business contexts.

Digital signatures rely on a public key infrastructure to establish trust in the subject of the signature. This trust occurs through the use of digital certificates issued by trusted certificate authorities that confirm the identity of the signer. This increases the credibility of the document.

Digital signatures make PDF documents more secure than their paper counterparts, reducing the risk of fraud. They can also be used to track the history of a document, showing who signed it and when, which is valuable for regulatory compliance and accountability.

Digital signatures eliminate the need for physical signatures, making signing documents more efficient and reducing the time and costs associated with printing, scanning and mailing paper documents.

Digital signatures on PDF files are widely used in many countries and industries, making them a practical and legally recognized way to sign and exchange documents internationally.

In general, digital signatures for PDF documents increase the security, reliability and efficiency of digital communication and document management. They play a critical role in today's business and legal landscape.

A web program for signing PDF files with a digital signature is offered to your attention! Whether you're using a computer or a mobile device, our easy-to-use platform allows you to sign PDF files on all operating systems without installing additional software. Our online software is free with no registration or code verification. We understand the importance of resource management, which is why our web application has an overall file size limit of 32 MB per pass. This ensures that you can process large amounts of data while maintaining optimal performance.

Although your files are stored on our server for 24 hours, we value your privacy, so we allow you to delete files immediately after processing.

Experience the convenience of our app, which is free and available on any desktop or mobile operating system, be it iPhone, Android, Linux, Windows or MacOS.

How it works


Select files

You can select files from the file system, Dropbox and Google Drive.


Type password


Press button "Sign"

in order to upload files for processing.


Wait for completion

It will take from 10 seconds to several minutes depending on the number and size of the files.


How does a digital signature work for PDF files?

Digital signatures for PDF files use a combination of public key infrastructure (PKI) technology. The document owner signs the PDF using their private key, and the recipient can verify the signature using the sender's public key.

Why use digital signatures for PDF files?

Digital signatures are used to authenticate the source of a PDF document, ensure its integrity, prevent unauthorized changes, establish non-repudiation, and enhance document security.

What is the difference between an electronic signature and a digital signature for PDF files?

Electronic signatures encompass a broad category of methods for signing documents electronically, while digital signatures specifically refer to a cryptographic signature that provides a higher level of security and non-repudiation.

What happens if someone tampers with a digitally signed PDF document?

If a digitally signed PDF document is altered, the signature becomes invalid, and the recipient will be alerted to the tampering. This ensures the document's integrity.