How to sign a digital document

As part of your work, the need to digitally sign documents has arisen. However, you have not yet been able to understand how the much talked about digital signature kits work and you are worried because you fear that you will not be able to meet some important deadlines that are approaching. No problem: I’m here to help you out. Regardless of what your needs are, in the guide I am about to offer you will find all the useful information on how to sign a digital document attributing legal value to it.

I guarantee you that, contrary to what you are thinking, there is nothing complicated about digitally signing your documents. And then you will agree with me that signing documents using the encryption systems that are the basis of the digital signature is really comfortable, as well as safe. While there are, if you are interested in doing so, in the last part of the tutorial I will also explain how to imprint your handwritten signature on digital documents even if, this is good for you to know right away, the latter has no legal value.

So, what are you doing still standing there? Courage: make yourself comfortable, take all the time you need to concentrate on reading the next paragraphs and, above all, implement the “tips” that I will give you. I am sure that, by following my advice carefully and scrupulously, you will eventually be perfectly able to sign your documents digitally. Enjoy the reading!

Index

• Types of digital signature
• How to obtain the digital signature
• How to sign a digital document with legal value
• How to sign a digital document without legal validity

Types of digital signature

Before going into the merits of the topic and seeing closely how to sign a digital document, I would like to give you a brief overview of the various types of digital signature you can use, some of which (as I told you in the introduction) have full legal value.

• “Simple” electronic signature– this type of signature, which can be affixed simply by “drawing” your signature on the screen or scanning it from a paper document, has no legal value. For what reason? Because the way in which this is affixed does not require the use of tools capable of guaranteeing the authenticity and integrity of the autographed documents. Only a judge can intervene and judge a signature of this type to be authentic or not (usually with the advice of a calligrapher expert).
• Advanced electronic signature– this is a type of electronic signature that is generated with the help of IT tools that allow you to demonstrate the integrity of the document, over which the user who affixes the signature has exclusive and direct control. For this reason, the advanced electronic signature has a certain legal value, even if this is not recognized in the stipulation of real estate contracts.
• Qualified electronic signature– this is one of the most advanced types of digital signature because it can be applied through the use of special kits issued by accredited certification bodies. Therefore it has a certain legal value and proves the originality and integrity of the signed documents.
• Digital electronic signature– this type of signature is the one that has full legal value since it involves the use of asymmetric cryptographic systems, in which a pair of keys (one public and one private) is used to verify the originality and integrity of signed documents.

If you wish to have some more knowledge on the differences between the various types of electronic signature currently available, you can refer to the in-depth analysis in which I explain what the digital signature is . Now, however, let’s see together how to get it.

How to obtain the digital signature

If you want to obtain a digital signature with certain legal value, you must start a procedure that is structured in three steps: the first is to purchase a digital signature kit; the second in verifying one’s identity and the third in activating the signature itself.

To purchase a digital signature kit, all you have to do is contact one of the companies certified by the Agency for Digital Italy  (eg  Aruba, Poste Italiane, etc.). The digital signature kits usually have prices that are around 50-60 euros and are composed of a plurality of devices (depending on the kit you decide to buy). Here are some of the main devices that make them up.

• USB key– as can be easily understood, these are USB sticks that integrate a smart card with the digital signature certificate, the software needed to sign documents and, sometimes, also the certificate for the National Service Card or CNS (a certificate that allows you to verify your identity in communications with the Public Administration): this is one of the most convenient solutions to use to digitally sign documents, as it does not require any software or driver installation and contains everything needed to affix the signature.
• USB tokens– these are also USB sticks that house a smart card, the certificate for digital signature and, sometimes, even the CNS. Unlike the previous solution, however, they require the installation of drivers and the installation of the applications necessary to sign documents. On the other hand, they are cheaper than the USB keys I mentioned earlier.
• Smart card reader– these are devices that read smart cards. They are combined with smart cards containing digital signature certificates and possibly the  CNS. They also provide for the installation of drivers and programs to digitally sign documents and have the advantage of being even cheaper than USB tokens. However, it must be recognized that they are a little more difficult to transport from one place to another, as they are much more bulky than the other solutions available.
• Remote digital signature kits – these are the most expensive kits, but they are also the only ones that allow you to digitally sign documents without using physical devices. Everything happens in a way thanks to the use of a “virtual” smart card, a disposable password that is generated from time to time by keys such as those provided by banks or sent via SMS and a signature and verification program.

Once you have purchased one of the digital signature kits from those indicated in the previous lines, you will need to verify your identity: an operation that can be done in various ways. You can, for example, carry out the ‘ identified visually by a public officer, exhibiting thus a valid ID and documentation received by the certifying; you can ask for the ‘ identification visually at the dispatch center by bringing you need that we talked about just now or you can do the’ identification visually home, providing the courier or postman with the identity document necessary for recognition.

Once this is done, you must activate the digital signature kit. Completing this last step is not complicated at all: you just have to follow the instructions given to you by the certified body that provided you with the kit. Usually you have to connect to the site of the latter, provide the information relating to the serial code of the smart card and your tax code (in addition to the personal activation code that will be sent to you via SMS) and that’s it.

After a certain period of time, usually 3 years, you will have to renew the digital signature certificates, subject to payment to the certifying body from which you purchased the kit.

How to sign a digital document with legal value

If you want to sign a legally valid digital document using the kit you previously purchased and activated, you need to launch the signature software that is included with it (if it is not included, you may need to download the necessary drivers to make it work and then download the software as well. software itself from the website of the certification body that provided you with the kit). Then you have to press the signature button and select the document – be it a PDF file, a Word document  or other. – on which you want to put the digital signature.

In the window that opens, you must then type the PIN of the smart card that contains your digital signature certificate in the appropriate text field and select the type of file you intend to obtain at the end of the operation. As you can see, you can choose between various types of files: P7M Encryption Envelope (CAdES) , to obtain a file in P7M format containing the original document and the digital signature files; PDF, to generate a PDF file with the digital signature included (whether it is visible or not) or  XML (XAdES)  to obtain also in this case a file in P7M format.

After choosing the type of file you want to obtain, you must start the application of the digital signature by pressing the appropriate button or, alternatively, apply a timestamp or a password to encrypt the file. In the first case, you can obtain a certification with which to verify the date and time in which the signature was placed on the document, allowing you to verify this data even if the signature certificate itself expires, while the second allows you to protect your document, allowing you to open it only to selected recipients, who are in possession of a public key.

Since the operation of each kit may slightly vary from one certification body to another, I suggest you refer to the official website of the company from which you purchased it (eg. Aruba, Postecert,  InfoCert, etc.) to be able to use without problems.

If you want to deepen the subject further and get more information on how to sign digitally, I suggest you consult the guide I just linked to. I am sure you will find it very useful.

How to sign a digital document without legal validity

As I mentioned in the introduction of the post, it is also possible to sign a digital document without legal validity, thus using the simple electronic signature. To do this, you don’t have to use any particular encryption system, but you can simply sign by writing it by hand (especially if the document in question is open on a device with a touch screen) or by scanning the signature from a paper document.

There are various programs and applications that allow you to do this, such as Adobe Acrobat Reader,  Nitro Rader, Preview (macOS’s default image and PDF reader), just to name a few. For more information on this kind of solutions, I invite you to read the in-depth study dedicated to digital signature programs: there you will find explained in greater detail how to affix your own simple electronic signature.