Which electronic signature should You choose for an online document? When is a one-time mSzafir enough?

Just a few years ago, many formalities required printing a document, signing it by hand and sending the paperwork back. Today, we handle them online. This is convenient, but it requires determining what level of reliability and legal validity a given electronic document requires.

What is a qualified electronic signature (QES)?

A qualified electronic signature is the digital equivalent of a handwritten signature with the same legal effect, thanks to its compliance with the EU eIDAS Regulation. It requires verification of the certificate holder’s identity and can only be issued by a qualified trust service provider listed on the European Union Trusted List (EUTL), such as KIR. The mSzafir mobile electronic signature is available as a one-time signature and as a long-term signature valid for one or two years.

Electronic document vs. electronic form – what is the difference in Poland?

These two terms sound similar and are often used interchangeably, which leads to many misunderstandings. An electronic document is a digital record of information. It can be a contract in PDF format, a scan or photo of a document, a form saved in a company system, or any file sent by email. An electronic form, on the other hand, refers to the method of making a declaration of intent (in accordance with Article 78¹ of the Polish Civil Code) using a qualified electronic signature.

Is every signature in a PDF valid?

This is one of the most frequently asked questions. Misunderstandings mainly arise because the term electronic signature is very broad. For some, it may mean an image of a handwritten signature inserted into a document. For others, it may mean typing their first and last name under a contract, clicking an “I Accept” button, or signing a document using PDF software.

Each of these methods can colloquially be called an electronic signature, but they do not all have the same legal effect. In the European Union, there are three levels of electronic signatures: simple, advanced and qualified. They differ primarily in how the signer’s identity is verified and in their level of reliability.

Only a qualified electronic signature is equivalent to a handwritten signature and can replace it wherever regulations require the electronic form to be maintained.

Why does Adobe show that the signature is valid?

Adobe Acrobat Reader and Acrobat Sign are used to sign and verify documents. When checking a file, the software verifies its integrity, the validity period of the certificate and who issued it. It uses both the European Union Trusted Lists (EUTL) and its own list of trusted certification authorities, the Adobe Approved Trust List (AATL).

It is important to remember, however, that not every certification authority is also a qualified trust service provider. Therefore, the message “Signature is valid” in Adobe confirms that the signature has been technically verified correctly. If a document requires a signature equivalent to a handwritten signature, a qualified electronic signature must be used. In Adobe’s signature panel, you can check the type of certificate and the entity that issued it.

When do You need a qualified electronic signature?

For individuals acting in a private capacity, a qualified e-signature is used to handle matters on their own behalf. This includes applications submitted to public authorities, powers of attorney for lawyers, statements submitted to medical facilities, or applications for grants related to public programmes.

A qualified signature for professional purposes is used to perform professional duties and conduct business activities. It is a convenient way to process contracts with business partners, HR documentation, insurance policies or tender offers.

One-time or long-term mSzafir?

Both variants require the generation of a qualified e-signature certificate and verification of its holder’s identity. What distinguishes them are the supported document formats and technical aspects.

One-time mSzafir was designed for people who sign documents infrequently, value their time or do not want to install additional software. All you need to do is purchase an e-signature for PLN 15 net, verify your identity using online banking or the mObywatel app (with an e-ID), generate a qualified certificate and sign the PDF. 

If signing documents becomes part of your daily work, long-term mSzafir will be a more convenient solution. It supports all file formats, including PDF, XML, binary data and ZIP. It allows you to authorise multiple files at once and gives you the flexibility to work from a mobile app, user portal or software installed on your computer.

For those who prefer to manage their signature on a physical device, we recommend the Szafir set with a cryptographic card and reader.

Frequently asked questions about signing electronic documents (FAQ)

The document signing process itself is simple. However, it is worth knowing a few rules that can make everyday work easier and help you make better use of the capabilities of a qualified certificate. That is why we have collected answers to the questions users ask most frequently.

How does a qualified certificate secure a document?

You do not need to be a cybersecurity specialist or understand the complexities of cryptography to use a qualified e-signature. When a document is signed, its content becomes permanently linked to a certificate containing the holder’s details. Technically, this involves creating a unique hash, which is encrypted using the private key of the person authorising the file.

When the document is opened, the system automatically reads the stored data using the public key and compares it with the current version of the file. If a single letter is changed after the file is signed, a duplicated space is removed, or an extra zero is added to the contract amount, the software will notify the recipient that the document does not match the original signed version.

A qualified e-signature therefore guarantees the authenticity and integrity of signed documents. The technology works in the background, while the user gets a secure, convenient and reliable online e-signature.

Do You need to sign every page of a document?

Initialling every page is a habit from traditional document workflows. It was intended to confirm that all parties had reviewed the content and make it more difficult to replace individual pages.

Electronic documents work differently. A qualified electronic signature secures the entire file, not just the page on which the signature appearance is visible. This means that any change to the content – whether it concerns the first, fifth or last page – will be detected when the document’s authenticity is verified.

You can, of course, sign each page separately if required by internal procedures or agreements between the parties. However, this does not affect the document’s level of security or legal effect. A single qualified signature is entirely sufficient to secure its entire content.

Can several people sign the same document?

Yes. A single document can be approved by several people, even if each person signs it in a different place and at a different time. Each subsequent signature is recorded in the document structure together with information about the certificate used.

Verification is simple: just open the file in an application that supports qualified e-signatures, such as Szafir. The software will display a list of the people who authorised the document, the dates on which the signatures were placed, and information on whether the certificates were valid when they were used.

What is a signature appearance and is it necessary?

A signature appearance is graphical information displayed on a document, including the certificate holder’s first and last name and the time when the qualified certificate was added. As a visual element, its absence does not affect the document’s formal validity. The recipient can verify the authenticity of the signature and the integrity of the file at any time using any verification tool.

The signature appearance is most commonly placed on the last page, where a traditional signature would normally be placed. When signing a document with one-time or long-term mSzafir, the user can choose whether and where the signature appearance should be displayed. To do this, simply open the file preview, go to the selected page and click the pen icon in the top-right corner. Then drag the signature to the desired location and close the preview to confirm the addition of the qualified certificate.

When one e-signature is not enough: solutions for businesses

One-time mSzafir is a good way to start using electronic document signing. If the number of files increases over time, it is worth choosing solutions tailored to everyday work. In such cases, we recommend the mSzafir long-term mobile signature or the Szafir set with a cryptographic card and reader.

For businesses looking to optimise their processes, we offer an integration option (including via API) with systems such as document management and workflow systems. Packages of one-time e-signatures are also a popular solution, for example, for employees signing contract amendments online. Implementing digital solutions is not only a step towards full digitalisation, but above all a tangible reduction in operating costs, elimination of printing and shorter processing times.