False Acceptance Ratio


False Acceptance Ratio (FAR), also known as False Acceptance Rate, is a performance metric used in biometric security systems. It measures the probability of a system incorrectly granting access to an unauthorized user by mistaking them for an authorized user. In simple terms, it refers to the percentage of times the system mistakenly allows access to the wrong person.


The phonetics of the keyword “False Acceptance Ratio” can be represented in the International Phonetic Alphabet (IPA) as: /ˈfɔls əkˈsɛptəns ˈreɪʃiˌoʊ/Here’s a breakdown of the pronunciation:- False: /ˈfɔls/- Acceptance: /əkˈsɛptəns/- Ratio: /ˈreɪʃiˌoʊ/

Key Takeaways

  1. False Acceptance Ratio (FAR) refers to the percentage of unauthorized users or impostors who are mistakenly granted access by a biometric security system.
  2. Reducing FAR is important for enhancing the security of a system, and it can be achieved by improving the algorithm used, increasing matching thresholds, and utilizing multi-factor authentication methods.
  3. A lower FAR value indicates better system performance and higher security, while a higher value implies increased chances of unauthorized access being granted.


The False Acceptance Ratio (FAR) is an important term in technology, particularly in the realm of biometric security systems, as it provides a significant measure of the system’s effectiveness and accuracy.

FAR refers to the likelihood that a system will erroneously accept an unauthorized user’s biometric input, granting them access to restricted information or resources.

A lower FAR indicates that the security system is more effective in distinguishing between the unique biometric identifiers of authorized and unauthorized users, thereby offering more robust protection.

By evaluating the False Acceptance Ratio, developers, organizations, and users can make well-informed decisions regarding the implementation and reliability of a given authentication system, striking a balance between security requirements and user convenience.


False Acceptance Ratio (FAR) plays a crucial role in enhancing security and privacy measures within various technological systems, particularly in the realm of biometrics and authentication processes. This metric serves as an indicator of how often an unauthorized user is mistakenly allowed access to a secured system, such as a smartphone, computer, or restricted area.

The purpose of FAR is to quantify the overall accuracy and effectiveness of biometric security systems, as it lets system developers and implementers understand and minimize the probability of erroneously granting access to illegitimate users, thus maintaining the integrity of a secured environment. Several industries employ False Acceptance Ratio to strike a balance between security and usability while setting up authentication protocols.

FAR influences the design and calibration of biometric systems, such as facial recognition, fingerprint scanners, and retina scanners, to name just a few. By adjusting various thresholds and system parameters, developers can optimize these technologies to reduce the likelihood of false acceptances without inadvertently increasing false rejection rates.

In summary, False Acceptance Ratio not only helps measure the overall reliability of a biometric technology, but also assists in fine-tuning the system, ultimately providing a seamless, secure user experience and protecting valuable assets from unauthorized access.

Examples of False Acceptance Ratio

The False Acceptance Ratio (FAR) is a measurement of a biometric authentication system’s accuracy in falsely accepting unauthorized individuals. Here are three real-world examples that demonstrate situations where the technology faces the challenge of false acceptance:

Smartphone biometrics: Modern smartphones often rely on biometric systems such as fingerprint sensors or facial recognition for unlocking the device. In 2017, a security firm, Bkav, claimed they were able to deceive the iPhone X’s facial recognition system (Face ID) by using a specially crafted mask. This demonstrated a situation where False Acceptance Ratio was a concern as the facial recognition system incorrectly granted access to an unauthorized individual.

Airport security and immigration controls: Biometric systems are widely used in airports for passport control and security checks, often utilizing facial recognition or fingerprint scans. In 2018, researchers from the Chaos Computer Club showed that the biometric authentication system used in German border control could be tricked with a modified passport, which contained adjusted facial features printed on the document. This example highlights the vulnerability of such systems to FAR.

Access control in workplaces and secure facilities: Biometric systems like fingerprint readers and facial recognition cameras are employed in workplaces or sensitive locations for access control and security. However, there have been reports of unauthorized access granted due to false acceptance incidents. In 2013, a hacker claimed to have successfully bypassed an Android phone’s fingerprint authentication with a 3D-printed fingerprint. This not only demonstrates the risk of false acceptance but also underscores the need for ongoing improvements to the technology to reduce FAR.

FAQ: False Acceptance Ratio

1. What is False Acceptance Ratio (FAR)?

False Acceptance Ratio, also known as False Accept Rate, is a biometric security performance metric that reflects the likelihood of a biometric security system incorrectly accepting an unauthorized user’s access attempt. It is typically expressed as a percentage or a proportion.

2. How is False Acceptance Ratio calculated?

False Acceptance Ratio is calculated by dividing the number of false acceptance instances by the total number of identification attempts made by unauthorized users. The result is multiplied by 100 to express it as a percentage.

3. How does False Acceptance Ratio impact a system’s security?

A high False Acceptance Ratio indicates that a biometric security system is more likely to falsely grant access to unauthorized users, which can potentially compromise the overall security of the system. A low False Acceptance Ratio suggests that the system is less likely to experience this compromise, thereby offering better security.

4. How can a biometric system’s False Acceptance Ratio be reduced?

Reducing the False Acceptance Ratio in a biometric system typically involves fine-tuning the system’s thresholds for accepting or rejecting access attempts. This can encompass improving the biometric sensor’s quality, employing more advanced algorithms for biometric data analysis, or incorporating additional biometric factors to strengthen the authentication process.

5. What is the difference between False Acceptance Ratio and False Rejection Ratio?

False Acceptance Ratio (FAR) refers to the probability of a biometric system erroneously granting access to an unauthorized user, while False Rejection Ratio (FRR) refers to the probability of the system mistakenly denying access to a legitimate user. Both FAR and FRR are important metrics in biometric system performance evaluation, with a need to strike a balance to optimize overall system performance.

Related Technology Terms

  • Biometric Authentication
  • False Rejection Ratio (FRR)
  • Equal Error Rate (EER)
  • Security Threshold
  • Biometric Error Rates

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