Passkey Authentication Information

What are Passkeys?

Passkeys are a modern, secure authentication method that completely replaces traditional passwords with cryptographic credentials.
They represent a revolutionary approach to user authentication, leveraging public-key cryptography to provide a more secure, user-friendly, and phishing-resistant authentication experience.

How Passkeys Work

Core Technology

Passkeys are built on the FIDO2/WebAuthn standard and use public-key cryptography principles:

Key Pair Generation: When you create a passkey, your device generates a unique cryptographic key pair:
- Private Key: Stored securely on your device (never leaves the device)
- Public Key: Shared with the service you’re registering with
Authentication Process:
- The service sends a challenge to your device
- Your device uses the private key to sign the challenge
- The service verifies the signature using the stored public key
- If verification succeeds, you’re authenticated

Security Features

Phishing Resistance

Domain Binding: Passkeys are cryptographically bound to specific domains
No Shared Secrets: Unlike passwords, there’s no secret that can be intercepted or stolen
Challenge-Response: Each authentication uses a unique challenge, preventing replay attacks

Application Scoping

Site-Specific: Each passkey is unique to the specific website or application
No Cross-Application Sharing: A passkey for one service cannot be used for another
Isolation: Compromising one service doesn’t affect other services

Important Clarification: While each site requires its own unique passkey, this doesn’t mean you need to authenticate every time you visit that site. The passkey is just the key - once you use it to unlock the door (authenticate), you stay inside (logged in) until the session expires.

Passkeys vs. JWT Bearer Tokens: A Common Comparison

How Passkeys Are Similar to JWT Bearer Tokens

Many developers compare passkeys to JWT bearer tokens, and there are indeed some similarities:

Site-Specific: Like JWT tokens, each passkey is unique to a specific site/application
No Cross-Site Usage: Just like you can’t use a JWT from Site A to authenticate to Site B
Authentication Proof: Both prove identity to the target service
Stateless Authentication: Both enable authentication without storing sensitive data server-side

The Authentication Flow Comparison

JWT Bearer Token Flow: 1. Login with username/password → Server generates JWT 2. Store JWT in browser/app 3. Send JWT with every subsequent API request 4. Server validates JWT on each request

Passkey Flow: 1. One-time registration → Device generates key pair 2. Store private key securely on device 3. Authentication challenge → Sign with private key 4. Server validates signature → Creates normal web session (cookies)

Passkeys + JWT Tokens: Working Together

Key Point: Passkeys replace passwords for authentication, but servers can still generate JWT tokens afterward for API access - giving you secure login plus efficient ongoing communication.

# Passkey Authentication Information ## What are Passkeys? Passkeys are a modern, secure authentication method that **completely replaces traditional passwords with cryptographic credentials**. They represent a revolutionary approach to user authentication, leveraging public-key cryptography to provide a **more secure**, **user-friendly**, and **phishing-resistant** authentication experience. ## How Passkeys Work ### Core Technology Passkeys are built on the **FIDO2/WebAuthn standard** and use **public-key cryptography** principles: 1. **Key Pair Generation**: When you create a passkey, your device generates a unique cryptographic key pair: - **Private Key**: Stored securely on your device (never leaves the device) - **Public Key**: Shared with the service you're registering with 2. **Authentication Process**: - The service sends a challenge to your device - Your device uses the private key to sign the challenge - The service verifies the signature using the stored public key - If verification succeeds, you're authenticated ### Security Features #### Phishing Resistance - **Domain Binding**: Passkeys are cryptographically bound to specific domains - **No Shared Secrets**: Unlike passwords, there's no secret that can be intercepted or stolen - **Challenge-Response**: Each authentication uses a unique challenge, preventing replay attacks #### Application Scoping - **Site-Specific**: Each passkey is unique to the specific website or application - **No Cross-Application Sharing**: A passkey for one service cannot be used for another - **Isolation**: Compromising one service doesn't affect other services **Important Clarification**: While each site requires its own unique passkey, this doesn't mean you need to authenticate every time you visit that site. The passkey is just the "key" - once you use it to unlock the door (authenticate), you stay "inside" (logged in) until the session expires. ### Passkeys vs. JWT Bearer Tokens: A Common Comparison #### How Passkeys Are Similar to JWT Bearer Tokens Many developers compare passkeys to JWT bearer tokens, and there are indeed some similarities: - **Site-Specific**: Like JWT tokens, each passkey is unique to a specific site/application - **No Cross-Site Usage**: Just like you can't use a JWT from Site A to authenticate to Site B - **Authentication Proof**: Both prove identity to the target service - **Stateless Authentication**: Both enable authentication without storing sensitive data server-side however please consider they are fundamentally different in how they in their purpose and usage: : | Aspect | JWT Bearer Tokens | Passkeys | |--------|------------------|----------| | **Storage** | Often stored in browser/app memory | Stored securely in device hardware/OS | | **Generation** | Generated by server after login | Generated by device during registration (and used during login) | | **Transmission** | Sent with every API request | Only used during authentication ceremony | | **Lifetime** | Have expiration times (minutes/hours) | Permanent until manually revoked | | **Security** | Can be intercepted if not secured | Cryptographically impossible to intercept | | **Usage Pattern** | Continuous usage for API calls | One-time usage for session establishment | #### The Authentication Flow Comparison **JWT Bearer Token Flow:** 1. Login with username/password → Server generates JWT 2. Store JWT in browser/app 3. Send JWT with every subsequent API request 4. Server validates JWT on each request **Passkey Flow:** 1. One-time registration → Device generates key pair 2. Store private key securely on device 3. Authentication challenge → Sign with private key 4. Server validates signature → Creates normal web session (cookies) #### Passkeys + JWT Tokens: Working Together **Key Point**: Passkeys replace passwords for authentication, but servers can still generate JWT tokens afterward for API access - giving you secure login plus efficient ongoing communication.