A biometric passport (also known as an e-passport or a digital passport) is a traditional passport that has an embedded electronic microprocessor chip which contains biometric information that can be used to authenticate the identity of the passport holder. It uses contactless smart card technology, including a microprocessor chip (computer chip) and antenna (for both power to the chip and communication) embedded in the front or back cover, or centre page, of the passport. The passport's critical information is printed on the data page of the passport, repeated on the machine readable lines and stored in the chip. Public key infrastructure (PKI) is used to authenticate the data stored electronically in the passport chip, making it expensive and difficult to forge when all security mechanisms are fully and correctly implemented. Many countries are moving towards issuing biometric passports to their citizens. Malaysia was the first country to issue biometric passports in 1998. In December 2008, 60 countries were issuing such passports, which increased to over 150 by mid-2019. The currently standardised biometrics used for this type of identification system are facial recognition, fingerprint recognition, and iris recognition. These were adopted after assessment of several different kinds of biometrics including retinal scan. Document and chip characteristics are documented in the International Civil Aviation Organization's (ICAO) Doc 9303 (ICAO 9303). The ICAO defines the biometric file formats and communication protocols to be used in passports. Only the digital image (usually in JPEG or JPEG 2000 format) of each biometric feature is actually stored in the chip. The comparison of biometric features is performed outside the passport chip by electronic border control systems (e-borders). To store biometric data on the contactless chip, it includes a minimum of 32 kilobytes of EEPROM storage memory, and runs on an interface in accordance with the ISO/IEC 14443 international standard, amongst others. These standards intend interoperability between different countries and different manufacturers of passport books. Some national identity cards, such as those from the Netherlands, Albania and Brazil, are fully ICAO 9303 compliant biometric travel documents. However others, such as the United States Passport Card, are not. Data protection Biometric passports have protection mechanisms to avoid and/or detect attacks: Non-traceable chip characteristics Random chip identifiers reply to each request with a different chip number. This prevents tracing of passport chips. Using random identification numbers is optional. Basic Access Control (BAC) BAC protects the communication channel between the