Criminalistics and Expertise Institute PZ: The act of signing must be taken seriously

If you were to advise companies on how to properly start using DVP (Digital Signature Pad), what would it be?

It is not possible to comment on security procedures, as each user company has personalized implementations within its security policy. However, from a handwriting expert’s perspective, it is crucial that when signing electronic documents using DVP, the aforementioned numerical data of signatures, i.e., the basic biometric data of the DVP, are captured and stored. Companies should be able to export and provide these data for forensic examination if needed. Additionally, they should be able to provide other important information, such as metadata about the digitalization device used, the signing software, conversion coefficients of values to basic or required units, information on the physical conditions in which the signers are signing, and so on. Companies should select and use high-quality solutions, as there are a wide variety of different digitizers and software available on the market. When signing at branches, conditions that closely simulate the typical environment of signing paper documents should be prepared for the client, such as a hard, flat, and stable surface, adjustable angle, and enough space to place the signature, etc.

What recommendations would you give to signers to develop the safest possible signing method? Should we change our signing style over time?

First and foremost, we would advise them to take the act of signing seriously and sign with their authentic signature expression, not just some random stroke. A spontaneous signature contains a security element inherent in the definition of a signature, and if they deprive themselves of this when authorizing important documents by using just a “scribble” instead of their signature, we cannot help them later if a problem arises. When building a signature at the beginning of their signing practice, it is a good idea to establish a more complex signature, whether it is readable, partially readable, or stylized (illegible). This means the signature should contain various loops, cross-strokes, and reversals, and that readable letters should not closely follow school norms in terms of shape, etc. The signature should be executed dynamically, as the signer's health and writing maturity allow. Signing styles naturally evolve over time and with practice frequency—sometimes the changes are significant and recognizable in stages, other times the transition is smooth without noticeable milestones. Some signers can maintain an absolutely consistent signing style throughout their lives. It is highly individual, just as each signer is unique. A handwriting expert must be able to properly evaluate this in each case based on comparative material, where the quality and quantity of such material are important.

We can’t do much if someone changes their signature after a name change or if someone significantly simplifies their signing style after taking on a job that requires signing large volumes of documents. We encounter this often. Again, it’s important to have enough appropriate comparative material from significant periods, allowing us to study the different signing styles of signers across various life stages or situations.

What advice would you give to signers (people signing documents with DVP in various contexts) to make this act of signing as secure as possible?

As already mentioned, first and foremost, they should genuinely try to sign as they normally would, which is probably the most important advice. Physical conditions when signing with DVP, such as a tablet with a slippery glass surface, limited space for the signature, or a digitizer that is placed awkwardly or uncomfortably, can affect the signer’s settings at the moment of signing and the resulting signature. However, these are also issues we encounter when examining classic signatures on paper, and we know how to evaluate them. If signers are used to signing important documents from home, they should invest in a high-quality signing device that captures all critical numerical data, including pressure. If possible, they should also use reliable signing technology and service providers who can offer these data for forensic examination if needed, demonstrating care for their clients.

Many companies, such as telecommunication operators, financial institutions, insurance companies, as well as entrepreneurs and individuals, allow and facilitate remote document signing (so-called “signing from the living room”). When signing remotely, devices that do not capture pressure data during signing with DVP are often used. In many cases, additional forms of signer verification, such as two-step authentication, are employed. Do you have any recommendations for signing in such cases (e.g., requesting multiple signatures, other alternatives)?

This additional form of verification can help companies authenticate the client and verify their identity, but it is irrelevant for us. When identifying the signer, we can only rely on our area of expertise: handwriting and signatures. Yes, if the signer produces multiple signatures without capturing pressure and we receive them for examination, this provides additional information about the signing behavior, which can be helpful. Pressure data are valuable for examination as well, but depending on the case, we can work without them, and their absence may or may not represent a limitation. It really depends on the case. Even if it is a limitation, it may not be significant enough to prevent a conclusion on the identification of the signer or to make it impossible to proceed with the examination. In this context, we strongly recommend that signers, even when signing from home, use the highest quality signing solutions—those that capture as much information about the signer’s signature as possible, including pressure.

What issues arise for handwriting examination when devices used for signing documents with DVP do not capture biometric data, or when user companies are unwilling or unable to provide these data for handwriting examination because they do not retain or export them?

When we are presented with just a “flat” PDF file containing an image of the DVP, it can lead to significant examination limitations, making it impossible to conclude the identification of the signer.

Do you think that DVP will completely replace traditional paper signatures in the future? What is the future of DVP from your perspective?

We don’t think so. Not all user entities find it worthwhile to invest in expensive technologies or processes for signing documents, especially if they don’t deal with a large number of clients. Many companies can simply administer paper documents, and the security of both types of signatures is comparable. We expect further development toward more advanced technologies and security, but we also anticipate a rise in user entities that reduce digital signing to the creation of “anything” on some active surface that doesn’t even capture necessary data. We hope the future of DVP will move toward safer signing, not only technologically but also from a handwriting expert’s perspective.

Is there a reason for law enforcement authorities and courts to treat the conclusions of expert reports on DVP examinations differently from those on traditional paper signature examinations in their decisions?

The principle of free evaluation of evidence applies in the Slovak legal system, so the final decision is in the hands of the courts. However, there is absolutely no reason to attribute different evidentiary weight to expert reports from DVP examinations compared to those from traditional paper signature examinations.