How Biometric Authentication Works: Benefits and Risks

Cybercrime is gaining scale worldwide, with global damages projected to reach $10.5 trillion in 2025. As attackers increasingly target digital identities and accounts, biometric authentication can help businesses verify that users are who they claim to be and reduce the risk of identity-related fraud. 

Biometrics confirm the person logging in is the legitimate holder of the identity or account. That cuts off the easiest routes to identity theft and account takeover, along with the unauthorized transactions that usually follow.

However, biometrics do have their risks. So let’s explore how biometric authentication works and weigh its pros and cons.

Biometric authentication defined: Key concepts

Biometric authentication involves verifying a person's identity by analyzing one or more of their distinctive physical and behavioral traits (through facial recognition, fingerprints, voice recognition, etc.).

Biometrics are used for authentication everywhere – from unlocking smartphones and accessing secure facilities to authorizing financial transactions and ensuring secure access to computer systems.

Biometric authentication is often confused with biometric verification, but the two slightly differ. Learn more in our guide to biometric verification.

Physical and behavioral biometric authentication methods

Biometric authentication methods can include physical and behavioral identifiers.

Physical biometric identifiers

Physical identifiers are relatively stable human characteristics, which include the following types of biometric authentication:

• Facial recognition: A technology that maps and measures facial features to identify or verify a person. It is an increasingly popular approach among online services, often used on smartphones.
• Fingerprint authentication: A technology that recognizes and verifies an individual's fingerprint. It is the most common type of biometric authentication and is built into most smartphones and laptops.
• Palm print: A technology that examines the unique patterns of veins and lines on the palm, as well as hand geometry (the shape and size of a person’s hand).
• Voice recognition: A technology that identifies a person based on their unique voiceprint. Telephone-based and digital service portals use it to authenticate customers.
• Retinal scan maps the unique pattern of blood vessels at the back of the eye using a low-power beam of light. 
• Iris recognition captures the iris pattern in the human eye. It’s considered one of the most accurate types of biometric identification and is faster and less intrusive than a retinal scan.
• DNA scan uses genetic material to identify a person and is commonly used by law enforcement to identify suspects.

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Behavioral biometric identifiers

Behavioral identifiers are patterns in how individuals perform activities, such as walking, speaking, or typing. Common examples include keystroke dynamics (the speed and rhythm of a person's typing), mouse and touchscreen dynamics (how someone moves a cursor, scrolls, or swipes), gait analysis (the way a person walks), and signature dynamics (the speed, pressure, and stroke order of a handwritten signature). 

Physical checks usually take place at a single moment, while behavioral data can be collected passively in the background as a person uses a device or app. Behavioral traits are less distinctive than physical ones and can change with mood, fatigue, or injury, so they're rarely used alone. More often, they serve as an extra risk signal that flags bots, remote-access tools, or someone other than the account holder, which makes them well suited to continuous authentication.

Advantages of biometric authentication over passwords

Biometric logins are preferable to passwords, PINs, or security tokens because they’re easier to use and more secure. Here are some of the key benefits:

• Strong security and lower risk of identity theft. Biometric traits are unique to each person and are difficult to replicate, which makes it harder for unauthorized users to gain access.
• Convenience. Biometric authentication eliminates the need to remember and manage passwords, so there's nothing to forget, reuse, or write down.
• Improved UX. Biometric authentication is usually quick. It reduces the time and effort required to access devices or services, which makes the user experience more pleasant.
• Low risk of human error. This type of authentication minimizes the potential for human error (typos when entering passwords or sharing passwords/credentials via emails or messages, etc.).
• Multi-factor authentication. Biometric methods can be used as part of multi-factor authentication, which combines multiple authentication factors for stronger security.
• Passkeys and passwordless biometric authentication. Biometrics can also be used to unlock other security credentials. For example, tools such as Face ID, Touch ID, and Windows Hello can unlock a private passkey locally (on your device) without needing to enter a password (called ‘passwordless authentication’), and this works with a public key held by a website or app to authenticate you. Your biometric data isn’t transmitted anywhere, which reduces the risk of theft. 
• Wide range of characteristics. Biometric authentication can use a wide range of characteristics, including physical (fingerprint, face, iris) and behavioral (e.g., typing pattern) traits.
• Future-proofing. Biometric traits remain relatively stable throughout a person's life, which eliminates the need for frequent updates or changes to authentication methods.

Despite these advantages, biometric authentication does come with a number of challenges.

Risks and challenges of biometric authentication

Some of the potential risks associated with biometric authentication are:

• Regulatory and compliance burden. Biometric data is highly personal and unique to each individual. Thus, the processing of biometric data requires special security and organizational measures to ensure an appropriate level of data security. Strict regulatory requirements and legal frameworks may also apply depending on the jurisdiction. Companies need to thoroughly examine these complexities to stay compliant with data protection laws.
• Data breaches. While data breaches are a risk when processing any type of personal data, the stakes are higher when dealing with biometrics. Unlike a password, stolen biometric data can't be reset – once compromised, it stays compromised and can be used for identity theft or unauthorized access.
• False positives and negatives. As with other types of data processing tools, biometric systems can occasionally produce false positives (incorrectly authenticating an unauthorized person) or false negatives (failing to authenticate an authorized user). These errors can impact both security and user experience.
• Forgery. Some biometric security systems can be fooled by high-quality replicas or "spoofs" of biometric features, such as fingerprints or facial features. Biometric spoofing can involve a photograph, 3D model, or silicone fingerprint replica used to bypass certain biometric security measures. 
• User apprehension. Some individuals may be uncomfortable with providing their biometric data due to privacy concerns, cultural reasons, or personal preferences. This can lead to adoption challenges.
• Injection and presentation attacks. Criminals can use “injection attacks” to feed false biometric data directly into a security system’s data stream, bypassing sensors (such as cameras and microphones). Presentation attacks, by contrast, show a fake biometric sample to the sensor itself. This can be as crude as holding up a printed photo, wearing a mask, or playing a video, or more sophisticated, e.g., using deepfake technology to create a highly convincing copy of a subject’s face or other biometric data source.

To address these challenges, organizations should pair biometrics with liveness and injection-attack detection, follow strong security practices, and comply with relevant regulations.

Use cases: Where biometric authentication is applied

Biometrics support both identity verification and ongoing authentication across industries, for example:

1. Identification and verification as part of Know Your Customer (KYC) procedures and anti-money laundering compliance, particularly in the financial sector.
2. Multi-factor authentication using biometrics for extra security. MFA combines two or more factors: something the customer knows (a PIN or password), has (a mobile device), or is (a biometric trait).
3. Prevention of account takeovers. This is especially relevant for industries like carsharing, payments, banking, and crypto. 
4. Prevention of promo abuse fraud. With a biometric check that matches new account data to existing customer profiles, business owners can ensure offers and special pricing plans go to first-time users only. This is especially relevant for gaming, streaming services, and delivery services.
5. Detection of arbitrage betting schemes.
6. Prevention of multi-accounting. This matters for peer-to-peer services, e-commerce, gaming, and streaming. Biometrics also help online education platforms stop account sharing, where several students use one paid account or, worse – someone else takes an exam.
7. Securing physical entrances. Biometrics can control access to doors, gates, and other entry points.
8. Verifying remote workers and preventing employment fraud.

Biometric authentication, deepfakes, and liveness detection

Deepfakes are more accessible than ever because AI tools are more widely available and more capable. They can be used for everything from bypassing age verification checks to helping criminals carry out advanced fraud operations. Deepfakes play a key role in the 180% surge in ‘sophisticated fraud’ from 2024 to 2025 uncovered in Sumsub’s 2025-2026 Identity Fraud Report.

Biometric authentication can play a significant role in combating the threats posed by deepfakes. Here’s how: 

Liveness detection verifies that biometric data is extracted from a live person, not a static image or video. By analyzing natural movements, liveness ensures real-time presence and counters deepfake attempts that use manipulated media. Sumsub’s Liveness Detection solution uses AI algorithms that can spot enhanced images.

Behavioral biometrics track patterns like typing speed and mouse movements to flag anomalies that suggest a bot, a remote-access tool, or someone other than the account holder.

Multi-factor authentication pairs a biometric check with at least one other factor, such as a password, a one-time passcode, or a physical security key. Combining biometric authentication with other verification methods, such as one-time passcodes, means a convincing deepfake alone isn't enough to get into an account.

Continuous biometric authentication beyond login

Most biometric authentication methods rely on verifying a user’s identity at a specific moment – when they log in to a system. Although this can be effective, it also creates a single point of failure: if a criminal beats biometric security at login, they gain full access to the user’s account.

Continuous biometric authentication removes a single point of failure, making it much harder for criminals to maintain access to an account even if they pass login authentication checks. It can be used with other methods, such as persistent KYC checks and ongoing transaction monitoring, to provide a comprehensive defense against illicit activity. 

Best practices for biometric authentication

An effective biometric authentication system should incorporate standard best practices, which include:

• Ensure regulatory compliance. Biometric authentication tools must comply with all relevant regulations and data protection laws.
• Implement security safeguards. Liveness checks, for instance, ensure biometric data belongs to a live, physically present user rather than a photograph, pre-recorded video, or deepfake.
• Allow for human review of biometric checks. This can help to ensure systems remain accountable and any problems are swiftly identified.
• Treat biometrics as one factor, not the whole system. Biometrics should form part of a broader authentication process. Biometric authentication can be used to activate or support another authenticator, such as a protected cryptographic key. 
• Build in both presentation attack and injection attack detection. Pairing liveness detection with injection-attack detection can significantly improve security. Tools built to stop presentation attacks don't automatically catch attacks on the data pipeline itself.
• Design for failure and fallback. Create a documented fallback path for failure-to-enroll or failure-to-verify cases. 
• Choose an independently verified vendor. Vendors’ solutions should pass presentation attack detection testing under ISO/IEC 30107-3 at an accredited lab such as iBeta. For example, Sumsub’s Liveness Solution passed iBeta Level 2 testing with a 0% attack presentation classification error rate – no spoof attempt was accepted.

FAQ: Biometric authentication questions

• How does biometric authentication work?

  Biometric authentication verifies a person’s identity by assessing one or more of their unique physical or behavioral characteristics (e.g., fingerprints, iris or retina, voice, face). The system captures biometrics (e.g., via a camera, fingerprint reader, or microphone), records distinctive data points, and converts them into a mathematical template. When authentication is required, the system captures a fresh recording of the subject’s biometrics and compares it to the stored template using a matching algorithm. If the similarity exceeds a set threshold, the system authenticates the person.

• Is biometric authentication safe?

  Generally yes. Biometric traits are unique and harder to replicate or share than a password or PIN. It's safest as one layer of account authentication, not the only layer.

• What is the difference between biometric and fingerprint authentication?

  Fingerprint authentication is one type of biometric authentication. Biometrics can also use other identifying traits, such as facial features. Fingerprint authentication uses the unique patterns of ridges and valleys on an individual's fingertip for identification, while biometrics use a broader range of a person’s traits to ensure the person is who they claim to be.

• Can biometrics be used for MFA?

  Yes, biometric authentication can be part of multi-factor authentication.

• What are the biometric data security risks?

  Potential data breaches are the biggest risk of using biometrics. If biometric data is compromised, it can’t be changed like a password or a PIN. Once biometric data is stolen, it is permanently compromised, potentially leading to identity theft or unauthorized access.

• Can biometric authentication be fooled?

  Biometrics are harder to bypass or fool than traditional authentication methods, like passwords. However, some biometric systems can be fooled with advanced deepfakes. It’s recommended to use advanced biometric systems supported by other authentication methods for extra security, or multimodal biometric authentication.

• Is biometric login safer than a password?

  In most cases, yes. Biometrics can't be forgotten, guessed, or phished the way passwords and PINs can. But biometric data can't be reset if stolen, so it's safest used with another factor.

• Are passkeys safer than passwords?

  Yes, passkeys are generally considered safer than passwords as they are phishing-resistant by design. This is because there's no shared secret information for an attacker to steal or trick a user into typing on a fake site. Nothing sensitive is stored on an organization’s server – only the public key is stored online, with the private key never leaving the user's device. As a result, a server-side data breach can't expose credentials the way a leaked password database can.