How Do Passkeys Work?

How do passkeys work?

Passkeys are an emerging technology aimed at enhancing security and convenience in digital authentication. Unlike traditional passwords, passkeys leverage cryptographic techniques to provide a more secure and user-friendly authentication method. Here's a detailed look at how passkeys work:

1. What Are Passkeys?

Passkeys are a type of cryptographic key pair used for authentication. They consist of two keys:

  • Public Key: Shared with the server and used for verification.
  • Private Key: Kept secret on the user's device and used for signing authentication requests.

2. How Passkeys Work

A. Registration

  1. User Initiates Registration: The user begins the registration process on a website or application.
  2. Key Pair Generation: The user's device generates a unique key pair (public and private keys).
  3. Public Key Sent to Server: The public key is sent to the server, which stores it along with the user's account information.
  4. Private Key Stored Locally: The private key remains on the user's device, secured by biometric data (like a fingerprint) or a PIN.

B. Authentication

  1. User Requests Authentication: When the user wants to log in, they initiate the authentication process.
  2. Server Sends Challenge: The server sends a cryptographic challenge to the user's device.
  3. User Unlocks Private Key: The user authenticates locally (e.g., using a fingerprint) to unlock the private key.
  4. Signing the Challenge: The device uses the private key to sign the challenge.
  5. Response Sent to Server: The signed challenge is sent back to the server.
  6. Verification: The server uses the stored public key to verify the signed challenge. If it matches, the user is authenticated.

3. Security Benefits

  • Phishing Resistance: Since passkeys are cryptographic, they are not susceptible to phishing attacks. A stolen public key is useless without the corresponding private key.
  • No Passwords to Remember: Users do not need to remember complex passwords, reducing the likelihood of weak passwords.
  • Biometric Integration: Passkeys often integrate with biometric authentication (like fingerprints or facial recognition), adding an extra layer of security.

4. User Experience

  • Seamless Authentication: Users can authenticate quickly and securely with a simple biometric scan or PIN.
  • Cross-Device Compatibility: Passkeys can be synchronized across devices using secure cloud services, ensuring users can access their accounts from multiple devices without compromising security.

5. Implementation Considerations

  • Device Support: Both the server and the user's device must support passkey technology.
  • Backup and Recovery: Users should have a backup method in case they lose access to their primary device (e.g., through a secondary device or account recovery options).

6. Future of Passkeys

Passkeys represent a significant advancement in authentication technology, potentially replacing passwords in many applications. As adoption grows, we can expect broader support across devices and platforms, leading to a more secure and user-friendly digital environment.


Passkeys offer a robust and user-friendly alternative to traditional passwords, leveraging advanced cryptographic techniques to enhance security and simplify the user experience. By eliminating the need for passwords and integrating biometric authentication, passkeys significantly reduce the risk of common security threats and streamline the authentication process.

Can passkeys be hacked?

Passkeys, like any technology, are not entirely immune to hacking. However, they are designed to be significantly more secure than traditional password-based systems. Here's a detailed look at potential vulnerabilities and how passkeys address them:

1. Cryptographic Security


  • Asymmetric Encryption: Passkeys use public-key cryptography, which is fundamentally secure if properly implemented. The private key never leaves the user's device, and the public key is only used for verification.
  • Phishing Resistance: Passkeys are resistant to phishing because even if an attacker obtains the public key, they cannot use it to authenticate without the private key.

Potential Vulnerabilities:

  • Weak Key Generation: If the cryptographic keys are not generated securely, they could be vulnerable to attacks. However, modern devices use strong, random key generation methods.
  • Quantum Computing: Future advances in quantum computing could theoretically break current cryptographic methods, but this is a concern for many cryptographic systems, not just passkeys.

2. Device Security


  • Local Storage of Private Key: The private key is stored securely on the user's device, often protected by hardware security modules (HSMs) or trusted platform modules (TPMs).
  • Biometric Authentication: Many implementations require biometric authentication (fingerprint, facial recognition) to access the private key, adding an extra layer of security.

Potential Vulnerabilities:

  • Device Compromise: If an attacker gains physical access to the user's device and bypasses the local security (e.g., biometric authentication), they could potentially use the private key.
  • Malware: Malware on the user's device could potentially intercept authentication processes, though this is mitigated by the secure storage and handling of private keys.

3. Server Security


  • Public Key Storage: The server only stores the public key, which cannot be used to impersonate the user without the private key.

Potential Vulnerabilities:

  • Server Breaches: If a server is breached, attackers could potentially alter stored public keys or inject malicious public keys. However, this requires a high level of sophistication and insider access.

4. Man-in-the-Middle Attacks


  • Signed Challenges: Passkeys involve signing a challenge from the server, which prevents man-in-the-middle attacks because the attacker cannot forge the signature without the private key.

Potential Vulnerabilities:

  • Initial Registration: If an attacker intercepts the initial registration process and injects their public key, they could potentially impersonate the user. Secure channels (like HTTPS) and device attestation can mitigate this risk.

Mitigations and Best Practices

To further enhance the security of passkeys, consider the following best practices:

  • Use Hardware Security Modules (HSMs): Store private keys in HSMs or TPMs to protect against physical attacks.
  • Biometric and Multi-Factor Authentication: Require biometric verification and/or multi-factor authentication to access private keys.
  • Regular Security Audits: Conduct regular security audits and updates to both client and server software.
  • Educate Users: Teach users about the importance of device security and recognizing phishing attempts.


While no system is entirely hack-proof, passkeys offer a significantly higher level of security compared to traditional passwords. Their design inherently mitigates many common attack vectors, making them a robust option for modern authentication needs. By following best practices and staying vigilant against emerging threats, the security of passkeys can be maintained effectively.

What are the pros and cons of passkeys?

Passkeys offer a promising alternative to traditional passwords, aiming to enhance both security and user experience. However, like any technology, they come with their own set of advantages and disadvantages. Here's a comprehensive look at the pros and cons of passkeys:


1. Enhanced Security

  • Phishing Resistance: Since passkeys use public-key cryptography, even if a user's public key is stolen, it cannot be used to authenticate without the private key.
  • No Passwords to Steal: Without passwords to steal, common attacks such as credential stuffing and brute-force attacks become ineffective.
  • Reduced Risk of Data Breaches: Servers only store public keys, which are useless without the corresponding private keys, reducing the impact of potential data breaches.

2. Improved User Experience

  • No Need to Remember Passwords: Users do not have to remember complex passwords, reducing cognitive load and improving convenience.
  • Fast and Seamless Authentication: Authentication can be as simple as a biometric scan or a PIN, making the process quicker and more user-friendly.
  • Consistent Across Devices: Passkeys can be synchronized across devices through secure cloud services, ensuring a seamless experience.

3. Stronger Authentication Methods

  • Biometric Integration: Many implementations of passkeys use biometric authentication, adding an additional layer of security.
  • Asymmetric Cryptography: The use of asymmetric cryptography ensures that the private key remains secure on the user's device, while the public key can be safely stored on the server.

4. Compatibility and Future-Proofing

  • Cross-Platform Support: Passkeys are designed to work across different platforms and devices, enhancing their utility in a diverse tech ecosystem.
  • Standardization: Industry standards such as FIDO2 and WebAuthn support passkeys, promoting broad adoption and interoperability.


1. Implementation Challenges

  • Device and Platform Support: Both users' devices and service providers' platforms must support passkey technology, which may require updates or changes to existing infrastructure.
  • Initial Setup Complexity: Setting up the infrastructure to support passkeys may require significant investment and technical expertise.

2. Dependency on Device Security

  • Device Compromise: If a user's device is compromised, the security of the passkeys stored on it could be at risk.
  • Loss or Damage of Device: Losing a device that stores private keys can be problematic if there are no robust backup or recovery options in place.

3. Usability Concerns

  • User Adaptation: Users accustomed to traditional passwords may take time to adapt to the new authentication method.
  • Biometric Limitations: Not all users may be able to use biometric authentication due to physical limitations or privacy concerns.

4. Backup and Recovery

  • Backup Solutions Needed: Users need reliable backup and recovery solutions to ensure they can still access their accounts if their primary device is lost or damaged.
  • Secondary Authentication: Implementing secondary authentication methods as a fallback can complicate the user experience and potentially introduce new security risks.

5. Potential for Misuse

  • Malware and Spyware: If malware or spyware infects a device, it could potentially intercept authentication processes or gain access to the private keys.


Passkeys offer a significant improvement over traditional passwords in terms of security and user experience. Their reliance on asymmetric cryptography and biometric authentication makes them resistant to many common attack vectors. However, they also introduce new challenges, such as the need for device security and reliable backup solutions. By carefully considering these pros and cons, organizations and users can make informed decisions about adopting passkeys as an authentication method.

Will passkeys replace passwords?

The question of whether passkeys will replace passwords involves examining both the technological advantages of passkeys and the practical considerations of widespread adoption. Here's a detailed analysis:

Technological Advantages of Passkeys

1. Enhanced Security

  • Phishing Resistance: Passkeys are inherently resistant to phishing attacks since they use cryptographic methods that do not rely on shared secrets (like passwords).
  • Reduction of Credential Theft: With passkeys, there are no passwords to steal, significantly reducing the risk of credential theft through data breaches.
  • Improved Authentication Methods: Passkeys often use biometrics or hardware-based security, adding additional layers of security.

2. User Experience

  • No Password Management: Users do not need to remember or manage complex passwords, reducing cognitive load and improving user experience.
  • Faster Authentication: Authentication with passkeys is generally quicker, often involving a biometric scan or a simple PIN.

3. Standardization and Interoperability

  • Industry Support: Standards like FIDO2 and WebAuthn provide a framework for implementing passkeys, ensuring broad support across devices and platforms.
  • Cross-Device Compatibility: Passkeys can be synchronized across devices, ensuring a seamless user experience.

Practical Considerations

1. Infrastructure and Implementation

  • Support and Compatibility: For passkeys to replace passwords, widespread support across devices, browsers, and services is necessary. This requires significant updates to existing systems.
  • Cost and Resources: Implementing passkey technology can be resource-intensive, requiring investment in new hardware, software, and training.

2. User Adoption

  • Transition Period: Users and organizations will need time to transition from passwords to passkeys. This transition period may involve using both methods in parallel.
  • User Education: Educating users about the benefits and usage of passkeys is crucial for successful adoption.

3. Backup and Recovery

  • Device Loss: Users need robust backup and recovery options in case they lose the device storing their private keys.
  • Fallback Methods: Providing secure and user-friendly fallback authentication methods is essential to ensure users can always access their accounts.

4. Security Concerns

  • Device Security: The security of passkeys depends heavily on the security of the user's device. If a device is compromised, the passkeys stored on it could be at risk.
  • Malware and Spyware: These threats could potentially intercept authentication processes or gain access to private keys.

Industry Trends and Future Outlook

1. Increasing Adoption

  • Tech Giants Leading the Way: Companies like Apple, Google, and Microsoft are increasingly supporting passkeys, indicating a strong industry push towards this technology.
  • Regulatory Influence: Regulatory requirements for stronger authentication methods could accelerate the adoption of passkeys.

2. Evolving Standards

  • Continuous Improvement: As standards like FIDO2 and WebAuthn evolve, they will likely address current limitations and make passkeys even more practical and secure.

3. User and Organizational Acceptance

  • Gradual Shift: The shift from passwords to passkeys is expected to be gradual, with both methods coexisting for some time.
  • Long-Term Replacement: In the long term, as more users and organizations experience the benefits of passkeys, passwords may become obsolete for most use cases.


Passkeys have the potential to replace passwords due to their superior security and user experience. However, the transition will take time, requiring widespread infrastructure changes, user education, and robust backup solutions. While passwords are likely to remain in use for some time, especially in legacy systems, the trend towards passkeys suggests that they could eventually become the primary method of authentication, significantly reducing reliance on traditional passwords.