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Check authenticity of documents

How to collect and verify identity documents to authenticate your users.

Check the identity of your customers remotely.

Performing an identity document verification check is essential to confirm the legitimacy and authenticity of an identity document, such as a passport, national identity card or driving licence.

An identity verification process will include checking the security features of the documents. For maximum effectiveness, identity documents should be checked by professionals trained in the techniques of detecting false documents.

With the proliferation of digital services and remote onboarding, online document fraud has increased. While governments and organizations that issue identity documents have always implemented security techniques to fight identity fraud, sometimes this is not enough. Fraudsters are developing more sophisticated techniques.

How can an identity document be checked?

  • Based on the identity document itself. Wherever possible, this approach should be preferred as it allows for more accurate checks through the use of specialized tools (e.g. ultraviolet light). 
  • Based on one or more images of the document. This is the most common approach when the check is carried out remotely (e.g. during an online verification). Or when verification is delegated to a centralized team of specialists.

Evolution of ID document checks.

  • Identity documents have always been checked by companies that request them, whether through a photocopy, scan or fax.
  • Document verification and control can now be done remotely and instantly. A visible 2D-DOC electronic stamp can be affixed to the documents to ensure security.
  • Over time, the evolution of document verification and control has been divided into two categories: documents with structured data (permits, passports, identity cards, etc.), and documents with unstructured data (invoices, IBAN, etc.).

How does document verification work?

When a document is submitted to a verification service, a set of automatic processing steps is performed. The following four steps are used in IDnow identity document checks.

1. Document classification

Without any input from the user, our services automatically identify the exact model of the identity document.

2. Data extraction

The data on the document holder is extracted from the different zones, such as the photo or the machine readable zone.

3. Document checks

In Unit Mode, also known as File Mode, several security checks are carried out: visual, business, consistency, blacklist.

4. Automated and real-time response

A verdict is given, together with a test report that is promptly returned to the customer.

Why use an identity document checker?

While many online businesses are not legally required to check the identity of their customers, they should consider doing so anyway to more effectively combat fraud.

Organizations from heavily regulated sectors, such as financial services or gambling, however, are legally required to check the age of their customers, along with other regulatory requirements.

An identity document checker can confirm details that are essential to comply with regulations, such as KYC (Know Your Customer), AML (Anti-Money Laundering), PEP (Politically Exposed Person) and CFT (Countering the Financing of Terrorism) requirements.

Identity documents supported.

Many documents can be used to prove identity:

  • ID card
  • Passport
  • Visa
  • Residence permit
  • Driving licence

These documents are usually issued by a trusted authority, such as a government, a recognized international organization, or a delegated entity.

Documents will contain the identity details of the holder like their surname, first name, date of birth, and address, as well as biometric information (photo, fingerprints) that allow the identity to be linked to the individual.

ID document verification: An effective way to fight fraud.

An identity document is issued after a rigorous process to ensure the document is produced on behalf of the right person and given to the right person.

The ID document should feature robust enough security measures to ensure criminals are unable to use the document for fraudulent purposes. Criminals often try to obtain identity documents that contain biometric characteristics associated with the identity of an existing person.

Commonly used identity documents vary from one country to another. In some countries, possession of an identity document (passport or identity card) is mandatory, while in others it is not. 

Most common identity documents.



Identity card

Identity Card

Residence permit

Residence Permit

Driving license

Driving license

Health insurance card

Health Insurance Card

Other supporting documents

Other Documents

Security features of identity documents.

There are many techniques for securing identity documents. As it is customary for documents to implement many security features to discourage or hinder criminal activity, we will present only the most commonly-used ones.

MRZ (Machine-Readable Zone)

The MRZ refers to a strip of one to three lines of characters found on documents. The strip contains important information in coded form. This includes the holder’s identity, date of birth, document expiry date, document number, etc. It also has the advantage of containing several checksums that can provide additional useful checks.

Special inks

Whether it is fluorescent, fugitive, iridescent, metallic, optically variable, photochromic, penetrating or thermochromic, ink plays a very important role in securing an identity document.

Special fonts

The use of special fonts that cannot be found in the public domain is an additional security feature.

Bar codes or 2D bar codes

Bar codes have been used on identity documents for several years. Initially one-dimensional, they are now two-dimensional, often in PDF417 format. The 2D-DOC code invented by the IDnow group has been presented to the International Civil Aviation Organization for further study on use in other identity documents.

Printing methods

The methods used to print document backgrounds or personalize the document are important security features. Even though they are often difficult to verify with the naked eye, offset, intaglio printing, typography, screen printing for the background, inkjet or laser printing, or thermal transfer all play a part in security measures.


Printing text incredibly small is extremely difficult to reproduce precisely enough with a traditional printer. Microprinting is used as a fairly effective security feature.

Embedding a contact or contactless chip

Embedded into the body of a polycarbonate card or the cover of a passport, an electronic chip adds a high level of security. It also offers the possibility of additional features, such as the possibility of checking the holder’s fingerprints.

Elements that respond with special lighting or at a specific angle

This category includes patterns sensitive to ultraviolet light, patterns that disappear under infrared light, holograms, fluorescent plates, etc.
Depending on the quality of the images uploaded for analysis, our automated identity verification solutions use algorithms to verify the most relevant security features.


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