Authentication is the process of verifying the identity of a user or process. There are three main types of authentication: knowledge-based authentication, possession-based authentication, and biometric authentication.
Knowledge-Based Authentication
Knowledge-based authentication, also known as something you know, relies on the user having access to a secret piece of information. The most common example is a password. Knowledge-based authentication verifies the user’s identity by prompting them to provide a pre-registered password. If the provided password matches the password on file for that user, the user’s identity is considered verified. Passwords are the most commonly used method of authentication. Most online accounts require a username and password to log in.
Other examples of knowledge-based authentication include:
- PIN numbers
- Passphrases
- Security questions
The main advantage of knowledge-based authentication is its simplicity and ease of use. Users only need to remember a piece of information. The main disadvantage is that stolen or guessed credentials allow unauthorized access. Passwords and other secrets should be kept confidential to maintain security.
Making Knowledge-Based Authentication More Secure
There are various methods to make knowledge-based authentication more secure:
- Use strong passwords – Longer passwords with a mix of uppercase, lowercase, numbers and symbols are harder to crack.
- Avoid common or guessable passwords – Information like birthdays or pet names should be avoided.
- Use passphrases – Longer passwords or passphrases are more secure than short passwords.
- Use multi-factor authentication – Combining a password with another factor like a one-time code makes it harder for attackers.
- Change passwords regularly – This limits the usefulness of compromised passwords.
- Use password managers – Tools like LastPass help generate and store strong, unique passwords.
Possession-Based Authentication
Possession-based authentication, also known as something you have, relies on the user having access to a physical object like a security token. The presence of the object proves the user’s identity. Common examples include key cards, security tokens and smartphone apps that generate login codes.
Other examples include:
- Keys
- ID cards
- Smart cards
Possession-based authentication has the advantage of being simple to use while also providing stronger security than knowledge-based factors alone. However, physical tokens can be stolen, copied or lost. Users must physically protect their authentication objects.
Strengthening Possession-Based Authentication
There are some techniques that can make possession-based authentication more secure:
- Use two-factor authentication – Combining a physical token with another factor like a password improves security.
- Use short-lived disposable tokens – One-time codes from a token generator or authenticator app are only valid for a short time.
- Use tamper-resistant hardware – Keys, cards and other devices that are difficult to duplicate or forge.
- Report lost or stolen objects – Promptly disabling compromised authentication objects prevents unauthorized access.
Biometric Authentication
Biometric authentication uses measurements of physical or behavioral characteristics to verify a user’s identity. Examples include fingerprints, facial recognition, iris/retina scans and voice recognition. Biometric factors utilize a person’s unique biological or behavioral traits. This provides convenient hands-free authentication that is difficult to imitate or share.
Common types of biometric authentication include:
- Fingerprint scanning
- Facial recognition
- Iris recognition
- Voice recognition
- Gait analysis (how someone walks)
Biometric authentication provides strong security as the factors being measured are difficult to spoof or share. It also avoids the need to memorize or carry additional authentication objects. However, specialized scanners and software are required to read biometric factors. There are also privacy concerns around the storage of sensitive biometric data.
Improving Security with Biometrics
Some techniques can enhance the security of biometric authentication:
- Use multi-factor authentication – Combining biometrics with a PIN or password is stronger than any factor alone.
- Use multiple biometric factors – Require matching fingerprint + iris scan for maximum security.
- Update stored templates frequently – Account for variations over time in biometric traits.
- Use liveness detection – Analyze that the biometric is coming from a live person and not a fake image.
- Use appropriate biometric – More distinctive traits like fingerprints are stronger than voice recognition.
Comparing the 3 Types of Authentication
Each type of authentication has its own strengths and weaknesses. Here is a comparison between the main authentication methods:
| Method | Security Strength | Usability | Cost |
|---|---|---|---|
| Knowledge Factors | Weak to Moderate | High | Low |
| Possession Factors | Moderate to Strong | Moderate | Low to Moderate |
| Biometric Factors | Strong | Moderate | High |
As seen above, knowledge factors like passwords have weak security but are inexpensive and easy to use. Possession-based authentication with security tokens provides improved security at moderate cost and usability. Biometric factors like fingerprints have strong security but require specialized scanners that increase cost.
Multi-Factor Authentication
Using multiple authentication factors in combination provides stronger security than any single factor alone. Multi-factor authentication requires the user to present multiple verified factors before being granted access.
Common methods include:
- Password + One-time code from authenticator app
- PIN + Fingerprint scan
- Security token + Facial recognition
Multi-factor authentication makes it much more difficult for an unauthorized person to access an account. If one factor is compromised, the attacker still needs to bypass the additional factor(s) before successfully authenticating as that user. This provides layered security.
Benefits of Multi-Factor Authentication
Multi-factor authentication offers a number of benefits including:
- Enhanced account security – Requires multiple factors that are difficult for attackers to access
- Fraud prevention – Makes unauthorized access much more difficult
- Regulatory compliance – Meets authentication requirements in many regulations
- User convenience – Can select factors based on availability, usability, cost
- Flexibility – Can combine factors to achieve the desired level of security
Implementing Multi-Factor Authentication
Here are some best practices for implementing multi-factor authentication:
- Use different factor types – Combine a knowledge factor with a possession or biometric factor.
- Allow users to select factors – Enables customization based on user needs.
- Support easy integration – Streamline adding MFA across applications, devices and operating systems.
- Provide fallback options – Alternate factors in case the primary option is unavailable.
- Use open standards – Standards like FIDO avoid vendor lock-in.
- Consider usability – Minimize user friction while still providing enhanced security.
Conclusion
The three main types of authentication each have unique strengths and weaknesses. Knowledge-based authentication using passwords is common but has security limitations. Possession-based methods improve security but require users to have access to a physical token. Biometric factors like fingerprints provide strong security but require specialized scanners and software.
Using multi-factor authentication combines the strengths of multiple methods for layered security. With proper implementation, organizations can optimize security, usability and cost-effectiveness. Understanding the different authentication factor types allows selecting the appropriate methods to meet an organization’s specific security and usability needs.