MRZ Basic Guide: Frequently Asked Questions

MRZ explicación

Have you ever stopped to think about how identity documents have adapted to globalization?

How do you verify the passport of a Spaniard in China?

Three letters: MRZ

What is the MRZ or Machine Readable Zone?

The MRZ or Machine Readable Zone is the part of an identity document, driver’s license, passport, etc., containing the identity data of a person in a language that a machine can understand.

It is 2 or 3 lines of coded information, a series of characters, numbers and separators whose initial objective was to speed up the automatic reading of a person’s personal data.

The MRZ provides personal data in a standard format to be automatically identified and extracted by a machine.

Did you know …?

In addition to personal data in standard format, the MRZ provides faster access to radio frequency identification (RFID) chips in biometric systems.

Why do MRZs arise?

The MRZ was born in the 1980s with the aim of streamlining identity verification processes at airports.

With the growth of international travelers and the growth of globalization, it became necessary to create an international standard for travel documents. Until then it was not possible to verify the identity documentation of foreigners.

For this reason, machine-readable travel documents began to be used in the 1980s to standardize and streamline the user verification process.

By the way, MRZ codes are regulated in the Doc 9303. Machine Readable Travel Documents from International Civil Aviation Organization.

How does the MRZ work? How is MRZ data read?

For an MRZ reader to understand the encoded data, an information extraction technology is needed. For this, an optical character recognition (OCR) system is used.

In this way, the MRZ data reading process could be summarized in three steps:

  1. MRZ scanning
  2. Data extraction thanks to OCR
  3. Verification and validation of the information, and / or external comparison with the document template identity

Or what is the same, the verification process requires a photograph of the identity document. An Optical Character Recognition (OCR) system recognizes the text and then automatically compares it to a code generated by an International Civil Aviation Organization (ICAO) algorithm (i.e. actual identity document templates). If any inconsistency or alteration is detected, it is considered fraud.

It should be noted that according to the ICAO standard, there are several Machine Readable Zone formats, depending on the document in which they are included.

For example, identity documents contain 3 lines of MRZ (30 characters each line); while the passports have 2 lines (44 characters each).

What does the MRZ tell us?

MRZ documents encode sensitive information in a visual format that can be easily read and decoded. This is basic information such as name and surname, nationality, type of document, date of birth, sex, etc.

Identity documents issued according to ICAO standards are made up of:

  • Visual Inspection Zone (VIZ), designed to be understood by people.

In this part, we find the image of the owner, personal data and data related to the issuance and validity of the document. date of birth, place, passport number, document issue date and expiration date.

This is information that can be understood at a glance.

  • Machine Readable Zone (MRZ), built for machines to understand (from software).

Here, in the machine readable zone, we have the same information, but in standard format. It is a pair of lines made up of digits, letters without special signs and filler characters, which also reveal the country of birth, name and surname, passport number, etc.

The MRZ contains digits, letters without special signs, and padding characters. The font used for these characters is defined by ICAO and has several different attributes.

The MRZ section of a passport contains personal information. It is important to keep it private. Today, there are numerous passport extraction APIs, which allow all the information of a person to be extracted from this section.

If you liked it, share it on