MRZ Code

The MRZ (Machine Readable Zone) code, found on passports, ID cards, and visas, consists of standardized characters specifically designed for Optical Character Recognition (OCR). It typically consists of two or three lines of text, printed at the bottom of the document’s biographical data page using a specialized, fixed-pitch font (OCR-B).
The primary purpose of MRZ is to enable fast, accurate, and automated data entry and verification by machine readers using OCR technology, significantly speeding up processes at border control, airports, and during digital Know Your Customer (KYC) onboarding.

What Does the MRZ Code Contain?

An MRZ encodes a compact set of identity and document fields in fixed positions. Depending on the document type, it typically includes:

• Document type (e.g., P for passport; I/A/C for ID cards/official docs)
  
• Issuing state/organization (modified ISO 3166-1 alpha-3 codes)
  
• Name (surname and given names with < as separator)
  
• Document number (with a check digit)
  
• Nationality
  
• Date of birth (YYMMDD, with a check digit)
  
• Sex
  
• Expiry date (YYMMDD, with a check digit)
  
• Optional/personal number (country-specific, often with a check digit)
  
• Final composite check digit (over multiple fields)
  

These fields and their lengths are fixed per MRZ type so software can parse them deterministically. 

How Does MRZ Work?

MRZ is essential for automated document verification, operating through a precise, three-step process: 

• Optical Scanning: A specialized MRZ reader or a standard camera (e.g., a smartphone camera used with verification software) captures an image of the MRZ lines.
• Data Extraction (OCR): Optical Character Recognition (OCR) software detects the MRZ area and instantly translates the high-contrast OCR-B characters into digital text. Because the MRZ fields are of a fixed, standardized length and position (e.g., the date of birth is always in the same location), the software can parse the data into its specific fields (Name, Date of Birth, Expiry Date, etc.) with very high accuracy.
• Data Validation: The system then mathematically recalculates the check digits for the extracted data fields. It compares its calculated check digits with the printed check digits in the MRZ. If all of them match, the system confirms that it has accurately read the data and that it aligns internally with the document’s printed information.

Why Is the MRZ Code Important for ID Verification?

The Machine Readable Zone (MRZ) is a crucial component for modern ID verification, owing to several compelling reasons, making it a cornerstone of secure and efficient identity checks across various sectors.

Speed & Efficiency

Automated data entry streamlines the process, replacing slow and error-prone manual typing with rapid data extraction and validation in seconds.

Standardization

Adhering to ICAO standards, MRZ provides a globally uniform data format. This ensures that a machine from any ICAO member state can read and understand the core data on a document issued by another, facilitating seamless international travel and verification.

Fraud Prevention

The inclusion of check digits acts as a powerful built-in security feature. Any unauthorized alteration (forgery) to a key data field (like the document number, date of birth, or expiration date) would change its calculated checksum, causing the MRZ reader to immediately flag the document as suspicious due to the mismatch.

Access to Biometric Data

On ePassports (biometric passports), the MRZ data (specifically the document number, date of birth, and expiry date) serves as the key. This key is essential for generating the access code needed to unlock and read the encrypted biometric data stored in the embedded RFID chip using Near-Field Communication (NFC).

Can MRZ be Forged or Manipulated?

While no security feature can claim absolute invulnerability, the Machine Readable Zone (MRZ) system is meticulously engineered to present formidable challenges to manipulation, making any attempts both difficult and readily detectable. This robust design incorporates several layers of defense against fraudulent activities.

Forgery of the Entire MRZ

A sophisticated forger could attempt to recreate the MRZ lines with a false name or number. However, the integrity check is the critical barrier. For the forgery to pass a machine scan, the forger must not only print the false data but also correctly calculate and print the corresponding, mathematically accurate check digits. Failing to do so will result in an immediate error flag from the scanner.

Document Alteration

When someone physically alters a legitimate document’s data such as the expiration date the machine reads the modified information. However, it calculates the check digit using the original printed value, which causes a mismatch and triggers fraud detection.

Standalone Vulnerability

MRZ itself, being printed text, is not encrypted. This is why modern verification systems never rely on MRZ alone. They cross-reference the extracted MRZ data against the Visual Inspection Zone (VIZ), the human-readable data printed on the document, and they use the MRZ data to unlock and verify the encrypted data on the biometric chip via NFC.

This is an excellent idea. A strong conclusion will summarize the key takeaways and reinforce the importance of the MRZ code in the broader context of identity verification.

How is a Passport’s MRZ Code Scanned?

A passport’s MRZ (TD3 format) is scanned using the following methods

Optical Character Recognition (OCR)

This is the most common method. An imaging device (like a camera or scanner) captures an image of the MRZ. Specialized software then analyzes the image to identify and extract the characters. OCR engines are trained on various fonts and character sets to accurately read the machine-readable text.

Near-Infrared (NIR) Scanning

Some passports incorporate security features that are only visible under near-infrared light. Scanning in NIR can help to verify the authenticity of the document and enhance the accuracy of character recognition, especially if visible light is obscured or the document is damaged.

UV (Ultraviolet) Scanning

Similar to NIR, UV light can reveal security features, such as fluorescent inks, that are embedded in passports. While not directly for reading the MRZ characters, UV scanning can be used in conjunction with other methods to ensure the document is genuine before the MRZ data is processed.

Visible Light Scanning

This is the most basic form and involves simply capturing an image of the MRZ under normal visible light. While effective for clear and undamaged documents, it may be less robust in challenging conditions or with certain security features.

Contact/Swipe Scanners

These devices often incorporate a slit where the passport is swiped through. They typically use a combination of visible light and potentially other light sources to capture the MRZ data as the document passes over a sensor.

Full-Page Document Scanners

These more advanced scanners can capture the entire passport page, including the MRZ, often in multiple light spectrums (visible, UV, IR) simultaneously. They are commonly used at border control and for more comprehensive document verification.

Mobile Device Cameras (with OCR software)

With the advancements in mobile technology, many applications can now use a smartphone’s camera to capture an image of the MRZ. Integrated OCR software then processes the image to extract the data. This method is convenient but can be more sensitive to lighting conditions and user technique.

What are the Benefits of the MRZ Code in Identity Verification?

The strategic integration of MRZ codes into verification systems offers profound benefits, primarily driven by efficiency and enhanced security. By automating the initial data capture, organizations achieve significant Cost Savings by replacing labor-intensive manual data entry. This automation not only drastically reduces the operational costs and time associated with processing documents but also minimizes the risk of human transcription errors, leading to near-zero error rates. The result is a substantial gain in UX, as the fast, frictionless scanning process is far smoother than traditional form-filling or check-in procedures.

Crucially, the MRZ system provides immediate security and compliance advantages. The globally recognized ICAO standards ensure Regulatory Compliance with various international frameworks like Know Your Customer (KYC) and Anti-Money Laundering (AML), as essential identity data is captured accurately and consistently, maintaining a verifiable audit trail. 

Furthermore, the inherent mathematical security of the MRZ enables a strong layer of fraud reduction. The built-in check digits serve as an initial, powerful filter that can instantly detect and flag simple counterfeits or tampering attempts where the document data and the calculated checksums do not match.

Finally, the MRZ is the foundation for modern biometric verification. For sophisticated security checks using ePassports and other electronic documents, the MRZ data (document number, date of birth, and expiry date) is the cryptographic key. 

By correctly reading these lines, verification platforms gain the necessary access to unlock and read the high-assurance, tamper-proof biometric and cryptographic data stored on the document’s embedded NFC chip, providing the ultimate level of identity assurance.